Merge feat/l1-workspace into integration branch

# Conflicts:
#	frontend/src/router.tsx

backend/app/api/deps.py

@@ -199,6 +199,53 @@ async def require_engineer_or_admin(
     )
 
 
+async def require_l1(
+    current_user: Annotated[User, Depends(get_current_active_user)]
+) -> User:
+    """L1 tech exact-match (with super_admin bypass for support)."""
+    if current_user.is_super_admin:
+        return current_user
+    if current_user.account_role != "l1_tech":
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="L1 tech role required",
+        )
+    return current_user
+
+
+async def require_l1_or_coverage(
+    current_user: Annotated[User, Depends(get_current_active_user)]
+) -> User:
+    """L1 endpoints: l1_tech, owners, super_admin, or engineers with can_cover_l1=True."""
+    if current_user.is_super_admin:
+        return current_user
+    role = current_user.account_role
+    if role == "l1_tech":
+        return current_user
+    if role == "owner":
+        return current_user
+    if role == "engineer" and current_user.can_cover_l1:
+        return current_user
+    raise HTTPException(
+        status_code=status.HTTP_403_FORBIDDEN,
+        detail="L1 access requires l1_tech role or engineer coverage flag",
+    )
+
+
+async def require_l1_or_above(
+    current_user: Annotated[User, Depends(get_current_active_user)]
+) -> User:
+    """Any tier from l1_tech upward (l1_tech, engineer, owner, super_admin)."""
+    if current_user.is_super_admin:
+        return current_user
+    if current_user.account_role in ("l1_tech", "engineer", "owner"):
+        return current_user
+    raise HTTPException(
+        status_code=status.HTTP_403_FORBIDDEN,
+        detail="L1 or above required",
+    )
+
+
 async def require_team_admin(
     current_user: Annotated[User, Depends(get_current_active_user)]
 ) -> User:

backend/app/api/endpoints/accounts.py

@@ -21,13 +21,54 @@ from app.models.subscription import Subscription
 from app.models.user import User
 from app.schemas.account import AccountResponse, AccountUpdate, AccountInviteCreate, AccountInviteResponse, AccountInviteBulkCreate, AccountInviteBulkResponse, TransferOwnershipRequest
 from app.schemas.subscription import SubscriptionResponse, PlanLimitsResponse, UsageResponse, SubscriptionDetails
-from app.schemas.user import UserResponse, AccountRoleUpdate
+from app.schemas.user import UserResponse, AccountRoleUpdate, CoverageUpdate
 from app.core.security import verify_password
-from app.api.deps import get_current_active_user, require_account_owner
+from app.api.deps import get_current_active_user, require_account_owner, require_engineer_or_admin
+from app.services.seat_enforcement import check_seat_available, get_seat_usage
+from app.schemas.seat_enforcement import SeatUsage
+
+_SEAT_CHECKED_ROLES = frozenset({"engineer", "l1_tech"})
 
 router = APIRouter(prefix="/accounts", tags=["accounts"])
 
 
+async def _load_account(db: AsyncSession, account_id: UUID) -> Account:
+    """Load an Account by id; raises 404 if missing."""
+    result = await db.execute(select(Account).where(Account.id == account_id))
+    account = result.scalar_one_or_none()
+    if account is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Account not found")
+    return account
+
+
+async def _enforce_seat_limit(db: AsyncSession, account_id: UUID, role: str) -> None:
+    """Raise HTTP 402 if the account has no capacity for the given role.
+
+    Only fires for seat-counted roles (engineer, l1_tech).
+    Accounts without a subscription (free / pre-billing) are not blocked.
+    Grandfathering: if current > limit, existing users keep access; this
+    helper only blocks new additions.
+    """
+    if role not in _SEAT_CHECKED_ROLES:
+        return
+    sub = await get_account_subscription(account_id, db)
+    if sub is None:
+        return  # no subscription → no enforcement
+    account = await _load_account(db, account_id)
+    seat_result = await check_seat_available(account, sub, role, db)
+    if not seat_result.available:
+        raise HTTPException(
+            status_code=status.HTTP_402_PAYMENT_REQUIRED,
+            detail={
+                "code": "seat_limit_exceeded",
+                "role": seat_result.role,
+                "current": seat_result.current,
+                "limit": seat_result.limit,
+                "upgrade_url": "/account/billing",
+            },
+        )
+
+
 @router.get("/me", response_model=AccountResponse)
 async def get_my_account(
     db: Annotated[AsyncSession, Depends(get_db)],
@@ -88,6 +129,41 @@ async def get_my_members(
     return result.scalars().all()
 
 
+@router.get("/me/seats", response_model=SeatUsage)
+async def get_my_account_seat_usage(
+    db: Annotated[AsyncSession, Depends(get_db)],
+    current_user: Annotated[User, Depends(require_engineer_or_admin)],
+):
+    """Returns engineer + l1_tech seat-usage counts. Accessible to engineer+.
+
+    Powers the SeatCounterWidget on admin/users and account/users surfaces.
+    """
+    account = await _load_account(db, current_user.account_id)
+    sub = await get_account_subscription(current_user.account_id, db)
+    if sub is None:
+        # No subscription → treat as unlimited; return live counts with no limit
+        from sqlalchemy import func
+        engineer_count = (await db.execute(
+            select(func.count(User.id))
+            .where(User.account_id == account.id)
+            .where(User.account_role == "engineer")
+            .where(User.is_active.is_(True))
+        )).scalar_one()
+        l1_count = (await db.execute(
+            select(func.count(User.id))
+            .where(User.account_id == account.id)
+            .where(User.account_role == "l1_tech")
+            .where(User.is_active.is_(True))
+        )).scalar_one()
+        from app.schemas.seat_enforcement import SeatCheckResult
+        return SeatUsage(
+            engineer=SeatCheckResult(available=True, current=engineer_count, limit=None, role="engineer"),
+            l1_tech=SeatCheckResult(available=True, current=l1_count, limit=None, role="l1_tech"),
+        )
+    engineer, l1_tech = await get_seat_usage(account, sub, db)
+    return SeatUsage(engineer=engineer, l1_tech=l1_tech)
+
+
 @router.patch("/me", response_model=AccountResponse)
 async def update_my_account(
     data: AccountUpdate,
@@ -141,12 +217,54 @@ async def update_member_role(
             detail="Cannot change your own role"
         )
 
+    # Seat enforcement: check capacity before promoting to a seat-counted role.
+    # Demotions (engineer/l1_tech → viewer) and lateral moves skip the check.
+    if data.account_role != user.account_role:
+        await _enforce_seat_limit(db, current_user.account_id, data.account_role)
+
     user.account_role = data.account_role
     await db.commit()
     await db.refresh(user)
     return user
 
 
+@router.patch("/me/members/{user_id}/coverage", response_model=UserResponse)
+async def update_member_coverage(
+    user_id: UUID,
+    data: CoverageUpdate,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    current_user: Annotated[User, Depends(require_account_owner)],
+):
+    """Toggle the `can_cover_l1` flag on an engineer in your account.
+
+    Owner-only. Returns 404 if target user not in your account. Returns 422
+    if target user's role is not 'engineer' (coverage flag only applies to
+    engineers — owners/super_admins already see L1 surface; viewers/l1_techs
+    don't need this flag).
+    """
+    result = await db.execute(
+        select(User).where(
+            User.id == user_id,
+            User.account_id == current_user.account_id,
+        )
+    )
+    target = result.scalar_one_or_none()
+    if target is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found in your account",
+        )
+    if target.account_role != "engineer":
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail="can_cover_l1 only applies to engineers",
+        )
+    target.can_cover_l1 = data.can_cover_l1
+    await db.commit()
+    await db.refresh(target)
+    return target
+
+
 @router.post("/me/transfer-ownership", response_model=AccountResponse)
 async def transfer_ownership(
     data: TransferOwnershipRequest,
@@ -261,6 +379,9 @@ async def create_invite(
     current_user: Annotated[User, Depends(require_account_owner)]
 ):
     """Create an invite to join this account (owner only). Sends invite email."""
+    # Seat enforcement: block invite if the target role is at capacity.
+    await _enforce_seat_limit(db, current_user.account_id, data.role)
+
     code = secrets.token_urlsafe(16)
 
     expires_at = None
@@ -317,6 +438,10 @@ async def create_invites_bulk(
     failed: list[dict] = []
     for invite_data in payload.invites:
         try:
+            # Seat enforcement per invite row — 402 bubbles as an HTTPException
+            # which is caught below and recorded in `failed`.
+            await _enforce_seat_limit(db, current_user.account_id, invite_data.role)
+
             code = secrets.token_urlsafe(16)
             expires_at = None
             if invite_data.expires_in_days:
@@ -343,6 +468,8 @@ async def create_invites_bulk(
                 invite.email_sent_at = datetime.now(timezone.utc)
 
             created.append(invite)
+        except HTTPException as exc:
+            failed.append({"email": invite_data.email, "error": exc.detail})
         except Exception as e:
             failed.append({"email": invite_data.email, "error": str(e)})
 

backend/app/api/endpoints/auth.py

@@ -289,6 +289,33 @@ async def register(
                     detail="Invite code has expired"
                 )
 
+    # Seat enforcement: re-check at accept time (race-condition guard).
+    # Fires only when an account invite is being accepted and the target role
+    # is seat-counted (engineer, l1_tech). Accounts without a subscription
+    # (free / pre-billing) are not blocked.
+    if account_invite_record and account_invite_record.role in ("engineer", "l1_tech"):
+        from app.core.subscriptions import get_account_subscription
+        from app.services.seat_enforcement import check_seat_available
+        from app.models.account import Account as _Account
+        sub = await get_account_subscription(account_invite_record.account_id, db)
+        if sub is not None:
+            acct_result = await db.execute(
+                select(_Account).where(_Account.id == account_invite_record.account_id)
+            )
+            acct = acct_result.scalar_one()
+            seat_result = await check_seat_available(acct, sub, account_invite_record.role, db)
+            if not seat_result.available:
+                raise HTTPException(
+                    status_code=status.HTTP_402_PAYMENT_REQUIRED,
+                    detail={
+                        "code": "seat_limit_exceeded",
+                        "role": seat_result.role,
+                        "current": seat_result.current,
+                        "limit": seat_result.limit,
+                        "upgrade_url": "/account/billing",
+                    },
+                )
+
     # Check if email already exists
     result = await db.execute(select(User).where(User.email == user_data.email))
     existing_user = result.scalar_one_or_none()

backend/app/api/endpoints/l1.py

@@ -0,0 +1,277 @@
+"""L1 Workspace endpoints (Phase 1).
+
+PSA-merge queue support + AI build path are deferred to Phase 2.
+"""
+from typing import Annotated, Optional
+from uuid import UUID
+
+from fastapi import APIRouter, Depends, HTTPException, status as http_status
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.deps import get_db, require_l1_or_coverage
+from app.models.l1_walk_session import L1WalkSession
+from app.models.user import User
+from app.schemas.l1 import (
+    EscalateRequest,
+    EscalateWithoutWalkRequest,
+    IntakeRequest,
+    IntakeResponse,
+    NotesRequest,
+    QueueRow,
+    ResolveRequest,
+    StepRequest,
+    WalkSessionResponse,
+)
+from app.services import internal_ticket_service, l1_session_service
+
+
+router = APIRouter(prefix="/l1", tags=["l1"])
+
+
+def _to_response(session: L1WalkSession) -> WalkSessionResponse:
+    return WalkSessionResponse(
+        id=session.id,
+        session_kind=session.session_kind,
+        flow_id=session.flow_id,
+        flow_proposal_id=session.flow_proposal_id,
+        current_node_id=session.current_node_id,
+        walked_path=session.walked_path or [],
+        walk_notes=session.walk_notes or [],
+        status=session.status,
+        started_at=session.started_at,
+        last_step_at=session.last_step_at,
+        resolved_at=session.resolved_at,
+    )
+
+
+async def _get_session_or_404(
+    db: AsyncSession, session_id: UUID, user: User
+) -> L1WalkSession:
+    """Fetch a session by id, scoped to the caller's account.
+
+    Phase 1 policy (per spec §7.9): sessions are account-scoped, not
+    user-scoped. Any L1 or coverage engineer in the same account can
+    step/note/resolve/escalate any session — supports team coverage
+    (e.g., L1 hands off mid-shift; coverage engineer takes over a call).
+    For a stricter "creator-only" policy, add
+    ``created_by_user_id == user.id`` here.
+    """
+    session = await db.get(L1WalkSession, session_id)
+    if session is None or session.account_id != user.account_id:
+        raise HTTPException(
+            status_code=http_status.HTTP_404_NOT_FOUND,
+            detail="Session not found",
+        )
+    return session
+
+
+@router.post("/intake", response_model=IntakeResponse)
+async def intake(
+    payload: IntakeRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    """L1 intake: creates an internal ticket and starts a walk session.
+
+    Phase 1: internal-ticket only (PSA support follows in Phase 2 escalation polish).
+    If `flow_id` is provided, starts a flow session; otherwise an adhoc session.
+    """
+    ticket = await internal_ticket_service.create_ticket(
+        db,
+        account_id=user.account_id,
+        created_by_user_id=user.id,
+        problem_statement=payload.problem_statement,
+        customer_name=payload.customer_name,
+        customer_contact=payload.customer_contact,
+    )
+    if payload.flow_id is not None:
+        session = await l1_session_service.start_flow_session(
+            db,
+            account_id=user.account_id,
+            user=user,
+            flow_id=payload.flow_id,
+            ticket_id=str(ticket.id),
+            ticket_kind="internal",
+        )
+    else:
+        session = await l1_session_service.start_adhoc_session(
+            db,
+            account_id=user.account_id,
+            user=user,
+            ticket_id=str(ticket.id),
+            ticket_kind="internal",
+        )
+    await db.commit()
+    return IntakeResponse(
+        session_id=session.id,
+        session_kind=session.session_kind,
+        ticket_id=str(ticket.id),
+        ticket_kind="internal",
+    )
+
+
+@router.get("/queue", response_model=list[QueueRow])
+async def queue(
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+    status_filter: Optional[str] = None,
+    limit: int = 50,
+):
+    """Phase 1 queue: internal tickets only. PSA-fed rows in Phase 2."""
+    tickets = await internal_ticket_service.list_tickets_for_account(
+        db,
+        account_id=user.account_id,
+        status=status_filter,
+        limit=limit,
+    )
+    return [
+        QueueRow(
+            ticket_id=str(t.id),
+            ticket_kind="internal",
+            problem_statement=t.problem_statement,
+            customer_name=t.customer_name,
+            status=t.status,
+            created_at=t.created_at,
+        )
+        for t in tickets
+    ]
+
+
+@router.get("/sessions/active", response_model=list[WalkSessionResponse])
+async def list_active_sessions(
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    """The caller's currently-active sessions (for the dashboard 'Resume in progress' widget)."""
+    stmt = (
+        select(L1WalkSession)
+        .where(L1WalkSession.created_by_user_id == user.id)
+        .where(L1WalkSession.status == "active")
+        .order_by(L1WalkSession.last_step_at.desc())
+        .limit(20)
+    )
+    result = await db.execute(stmt)
+    return [_to_response(s) for s in result.scalars()]
+
+
+@router.get("/sessions/{session_id}", response_model=WalkSessionResponse)
+async def get_session(
+    session_id: UUID,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    session = await _get_session_or_404(db, session_id, user)
+    return _to_response(session)
+
+
+@router.post("/sessions/{session_id}/step", response_model=WalkSessionResponse)
+async def post_step(
+    session_id: UUID,
+    payload: StepRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    await _get_session_or_404(db, session_id, user)
+    try:
+        updated = await l1_session_service.record_step(
+            db,
+            session_id=session_id,
+            node_id=payload.node_id,
+            question=payload.question,
+            answer=payload.answer,
+            note=payload.note,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=http_status.HTTP_400_BAD_REQUEST, detail=str(exc))
+    await db.commit()
+    return _to_response(updated)
+
+
+@router.post("/sessions/{session_id}/notes", response_model=WalkSessionResponse)
+async def post_notes(
+    session_id: UUID,
+    payload: NotesRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    await _get_session_or_404(db, session_id, user)
+    try:
+        updated = await l1_session_service.update_notes(
+            db,
+            session_id=session_id,
+            notes=payload.notes,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=http_status.HTTP_400_BAD_REQUEST, detail=str(exc))
+    await db.commit()
+    return _to_response(updated)
+
+
+@router.post("/sessions/{session_id}/resolve", response_model=WalkSessionResponse)
+async def post_resolve(
+    session_id: UUID,
+    payload: ResolveRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    await _get_session_or_404(db, session_id, user)
+    try:
+        updated = await l1_session_service.resolve(
+            db,
+            session_id=session_id,
+            helpful=payload.helpful,
+            resolution_notes=payload.resolution_notes,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=http_status.HTTP_400_BAD_REQUEST, detail=str(exc))
+    await db.commit()
+    return _to_response(updated)
+
+
+@router.post("/sessions/{session_id}/escalate", response_model=WalkSessionResponse)
+async def post_escalate(
+    session_id: UUID,
+    payload: EscalateRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    await _get_session_or_404(db, session_id, user)
+    try:
+        updated = await l1_session_service.escalate(
+            db,
+            session_id=session_id,
+            reason=payload.reason or "",
+            reason_category=payload.reason_category,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=http_status.HTTP_400_BAD_REQUEST, detail=str(exc))
+    await db.commit()
+    return _to_response(updated)
+
+
+@router.post("/escalate-without-walk", response_model=WalkSessionResponse)
+async def post_escalate_without_walk(
+    payload: EscalateWithoutWalkRequest,
+    db: Annotated[AsyncSession, Depends(get_db)],
+    user: Annotated[User, Depends(require_l1_or_coverage)],
+):
+    ticket = await internal_ticket_service.create_ticket(
+        db,
+        account_id=user.account_id,
+        created_by_user_id=user.id,
+        problem_statement=payload.problem_statement,
+        customer_name=payload.customer_name,
+        customer_contact=payload.customer_contact,
+    )
+    session = await l1_session_service.escalate_without_walk(
+        db,
+        account_id=user.account_id,
+        user=user,
+        ticket_id=str(ticket.id),
+        ticket_kind="internal",
+        reason_category=payload.reason_category,
+        reason=payload.reason,
+    )
+    await db.commit()
+    return _to_response(session)

backend/app/api/endpoints/oauth.py

@@ -3,7 +3,7 @@ import string
 from datetime import datetime, timezone
 from typing import Annotated
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -118,6 +118,29 @@ async def _sign_in_or_register(
 
     if is_new_user:
         if invite_record is not None:
+            # Seat enforcement: re-check at OAuth accept time (race-condition guard).
+            if invite_record.role in ("engineer", "l1_tech"):
+                from app.core.subscriptions import get_account_subscription
+                from app.services.seat_enforcement import check_seat_available
+                sub = await get_account_subscription(invite_record.account_id, db)
+                if sub is not None:
+                    acct_result = await db.execute(
+                        select(Account).where(Account.id == invite_record.account_id)
+                    )
+                    acct = acct_result.scalar_one()
+                    seat_result = await check_seat_available(acct, sub, invite_record.role, db)
+                    if not seat_result.available:
+                        raise HTTPException(
+                            status_code=status.HTTP_402_PAYMENT_REQUIRED,
+                            detail={
+                                "code": "seat_limit_exceeded",
+                                "role": seat_result.role,
+                                "current": seat_result.current,
+                                "limit": seat_result.limit,
+                                "upgrade_url": "/account/billing",
+                            },
+                        )
+
             # Join the invited account directly — no personal account, no
             # trial creation.
             user = User(

backend/app/api/router.py

@@ -8,6 +8,7 @@ from app.api.deps import (
 from app.api.endpoints import (
     admin,
     admin_audit,
+    l1,
     admin_categories,
     admin_dashboard,
     admin_feature_flags,
@@ -185,3 +186,6 @@ api_router.include_router(beta_feedback.router, dependencies=_tenant_deps)
 api_router.include_router(session_branches.router, dependencies=_pro_deps)
 api_router.include_router(session_handoffs.router, dependencies=_pro_deps)
 api_router.include_router(device_types.router, dependencies=_tenant_deps)
+# L1 is a separate seat-counted SKU; subscription gating is enforced by
+# seat_enforcement (engineer + l1_seat_limit), not require_active_subscription.
+api_router.include_router(l1.router, dependencies=_tenant_deps)

backend/app/core/audit.py

@@ -13,13 +13,20 @@ async def log_audit(
     resource_id: Optional[UUID] = None,
     details: Optional[dict] = None,
     account_id: Optional[UUID] = None,
+    acting_as: Optional[str] = None,
 ) -> None:
-    """Record an audit log entry. Does not commit — piggybacks on the caller's commit."""
+    """Record an audit log entry. Does not commit — caller's commit picks it up.
+
+    acting_as: optional tag from the session (e.g. 'l1_coverage' for engineers
+    on the L1 surface, None for native l1_tech users).
+    """
     if account_id is None:
         # Derive from the acting user's account as a fallback (one extra query).
         from sqlalchemy import select
         from app.models.user import User
-        result = await db.execute(select(User.account_id).where(User.id == user_id))
+        result = await db.execute(
+            select(User.account_id).where(User.id == user_id)
+        )
         account_id = result.scalar_one()
 
     entry = AuditLog(
@@ -29,5 +36,6 @@ async def log_audit(
         resource_type=resource_type,
         resource_id=resource_id,
         details=details,
+        acting_as=acting_as,
     )
     db.add(entry)

backend/app/core/permissions.py

@@ -1,11 +1,12 @@
 """
 Centralized permission checks for ResolutionFlow.
 
-Role hierarchy: super_admin > owner > engineer > viewer
+Role hierarchy: super_admin > owner > engineer > l1_tech > viewer
 
 - super_admin: is_super_admin=True, full system access
 - owner:       account_role='owner', manage account resources
 - engineer:    account_role='engineer' (default), CRUD own trees/steps
+- l1_tech:     account_role='l1_tech', use /l1/* surface only — walk flows, resolve/escalate
 - viewer:      account_role='viewer', read-only (can browse, run sessions, rate steps)
 """
 from __future__ import annotations
@@ -23,7 +24,8 @@ ROLE_HIERARCHY = {
     "super_admin": 4,
     "owner": 3,
     "engineer": 2,
-    "viewer": 1,
+    "l1_tech": 1,
+    "viewer": 0,
 }
 
 

backend/app/main.py

@@ -221,6 +221,18 @@ async def lifespan(app: FastAPI):
         max_instances=1,
     )
 
+    # L1 walk session cleanup: flip stale active sessions to 'abandoned' (hourly)
+    from app.services.l1_session_cleanup import run_cleanup_job as l1_cleanup_run
+    scheduler.add_job(
+        l1_cleanup_run,
+        trigger="interval",
+        hours=1,
+        id="l1_session_cleanup",
+        replace_existing=True,
+        max_instances=1,
+        args=[async_session_maker],
+    )
+
     # Auto-seed trees in background on PR environments
     seed_task = None
     if settings.SEED_ON_DEPLOY:

backend/app/models/__init__.py

@@ -66,6 +66,8 @@ from .oauth_identity import OAuthIdentity  # noqa: F401
 from .plan_billing import PlanBilling  # noqa: F401
 from .sales_lead import SalesLead  # noqa: F401
 from .stripe_event import StripeEvent  # noqa: F401
+from .internal_ticket import InternalTicket  # noqa: F401
+from .l1_walk_session import L1WalkSession  # noqa: F401
 
 __all__ = [
     "User",
@@ -146,4 +148,6 @@ __all__ = [
     "PlanBilling",
     "SalesLead",
     "StripeEvent",
+    "InternalTicket",
+    "L1WalkSession",
 ]

backend/app/models/account.py

@@ -57,6 +57,11 @@ class Account(Base):
     team_size_bucket: Mapped[Optional[str]] = mapped_column(String(20), nullable=True)
     primary_psa: Mapped[Optional[str]] = mapped_column(String(20), nullable=True)
 
+    # L1 workspace seats
+    l1_seats_purchased: Mapped[int] = mapped_column(
+        Integer, nullable=False, server_default="0"
+    )
+
     # SSO / SAML groundwork (Task 11)
     sso_enabled: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
     sso_provider: Mapped[Optional[str]] = mapped_column(String(20), nullable=True)  # "saml" | "oidc"

backend/app/models/audit_log.py

@@ -35,6 +35,7 @@ class AuditLog(Base):
     )
     details: Mapped[Optional[dict]] = mapped_column(JSONB, nullable=True)
     ip_address: Mapped[Optional[str]] = mapped_column(String(45), nullable=True)
+    acting_as: Mapped[Optional[str]] = mapped_column(String(30), nullable=True)
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True),
         default=lambda: datetime.now(timezone.utc)

backend/app/models/flow_proposal.py

@@ -7,7 +7,7 @@ import uuid
 from datetime import datetime, timezone
 from typing import Optional, Any, TYPE_CHECKING
 
-from sqlalchemy import String, Text, DateTime, ForeignKey, Integer, Float, CheckConstraint
+from sqlalchemy import String, Text, DateTime, ForeignKey, Integer, Float, Boolean, CheckConstraint, text as sa_text
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 from sqlalchemy.dialects.postgresql import UUID, JSONB
 
@@ -48,6 +48,14 @@ class FlowProposal(Base):
             "status IN ('pending', 'approved', 'modified', 'rejected', 'dismissed', 'auto_reinforced')",
             name="ck_flow_proposals_status",
         ),
+        CheckConstraint(
+            "source IN ('ai_realtime_l1', 'kb_accelerator', 'manual_draft', 'ai_promoted')",
+            name="ck_flow_proposals_source",
+        ),
+        CheckConstraint(
+            "linked_ticket_kind IS NULL OR linked_ticket_kind IN ('psa', 'internal')",
+            name="ck_flow_proposals_linked_ticket_kind",
+        ),
     )
 
     id: Mapped[uuid.UUID] = mapped_column(
@@ -135,6 +143,16 @@ class FlowProposal(Base):
         comment="The flow that was created/updated when this proposal was approved",
     )
 
+    # ── L1 workspace ──
+    source: Mapped[str] = mapped_column(
+        String(30), nullable=False, server_default=sa_text("'manual_draft'"),
+    )
+    linked_ticket_id: Mapped[Optional[str]] = mapped_column(String(64), nullable=True)
+    linked_ticket_kind: Mapped[Optional[str]] = mapped_column(String(10), nullable=True)
+    validated_by_outcome: Mapped[bool] = mapped_column(
+        Boolean(), nullable=False, server_default=sa_text('false'),
+    )
+
     # ── Timestamps ──
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)

backend/app/models/internal_ticket.py

@@ -0,0 +1,117 @@
+"""Internal ticket model.
+
+Fallback ticket table for L1 intake when the account has no PSA integration.
+Tracks the customer-facing problem, resolution lifecycle, and optional links
+to a flow, flow proposal, AI session, and assigned engineer.
+"""
+import uuid
+from datetime import datetime, timezone
+from typing import Optional, TYPE_CHECKING
+
+from sqlalchemy import String, Text, DateTime, ForeignKey, CheckConstraint
+from sqlalchemy import text as sa_text
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.dialects.postgresql import UUID
+
+from app.core.database import Base
+
+if TYPE_CHECKING:
+    from app.models.account import Account
+    from app.models.user import User
+    from app.models.tree import Tree
+    from app.models.flow_proposal import FlowProposal
+    from app.models.ai_session import AISession
+
+
+class InternalTicket(Base):
+    """A fallback support ticket for accounts without a PSA integration.
+
+    status lifecycle:
+    - open: Submitted, not yet picked up.
+    - walking: L1 technician is actively walking the flow.
+    - resolved: Issue resolved; resolution_notes captured.
+    - escalated: Could not resolve; requires higher-tier intervention.
+    """
+    __tablename__ = "internal_tickets"
+    __table_args__ = (
+        CheckConstraint(
+            "status IN ('open', 'walking', 'resolved', 'escalated')",
+            name="ck_internal_tickets_status",
+        ),
+    )
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    account_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("accounts.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    created_by_user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="RESTRICT"),
+        nullable=False,
+    )
+
+    # ── Customer info ──
+    customer_name: Mapped[Optional[str]] = mapped_column(String(120), nullable=True)
+    customer_contact: Mapped[Optional[str]] = mapped_column(String(200), nullable=True)
+    problem_statement: Mapped[str] = mapped_column(Text(), nullable=False)
+
+    # ── Lifecycle ──
+    status: Mapped[str] = mapped_column(
+        String(30), nullable=False, server_default=sa_text("'open'"), index=True,
+    )
+
+    # ── Optional links ──
+    flow_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("trees.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    flow_proposal_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("flow_proposals.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    ai_session_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("ai_sessions.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    assigned_user_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+        index=True,
+    )
+
+    # ── Resolution ──
+    resolution_notes: Mapped[Optional[str]] = mapped_column(Text(), nullable=True)
+    psa_promoted_ticket_id: Mapped[Optional[str]] = mapped_column(
+        String(64), nullable=True,
+        comment="External PSA ticket ID when this ticket is promoted to a PSA system",
+    )
+
+    # ── Timestamps ──
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+    )
+    resolved_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True), nullable=True,
+    )
+
+    # ── Relationships ──
+    account: Mapped["Account"] = relationship("Account")
+    created_by: Mapped["User"] = relationship("User", foreign_keys=[created_by_user_id])
+    assigned_user: Mapped[Optional["User"]] = relationship("User", foreign_keys=[assigned_user_id])
+    flow: Mapped[Optional["Tree"]] = relationship("Tree")
+    flow_proposal: Mapped[Optional["FlowProposal"]] = relationship("FlowProposal")
+    ai_session: Mapped[Optional["AISession"]] = relationship("AISession")

backend/app/models/l1_walk_session.py

@@ -0,0 +1,141 @@
+"""L1 walk session model.
+
+Per-session state for an L1 technician walking a ticket through a flow,
+flow proposal, or ad-hoc investigation. Tracks the walked path, notes
+captured at each step, and terminal resolution / escalation metadata.
+"""
+import uuid
+from datetime import datetime, timezone
+from typing import Any, Optional, TYPE_CHECKING
+
+import sqlalchemy as sa
+from sqlalchemy import String, Text, DateTime, Boolean, ForeignKey, CheckConstraint
+from sqlalchemy import text as sa_text
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.dialects.postgresql import UUID, JSONB
+
+from app.core.database import Base
+
+if TYPE_CHECKING:
+    from app.models.account import Account
+    from app.models.user import User
+    from app.models.tree import Tree
+    from app.models.flow_proposal import FlowProposal
+
+
+class L1WalkSession(Base):
+    """A single L1 technician session walking a ticket.
+
+    session_kind values:
+    - flow: Walking a published flow (flow_id required, flow_proposal_id null).
+    - proposal: Walking a draft flow proposal (flow_proposal_id required, flow_id null).
+    - adhoc: Free-form investigation (both flow_id and flow_proposal_id null).
+
+    status lifecycle:
+    - active: Session is in progress.
+    - resolved: Issue resolved; resolution_notes captured.
+    - escalated: Could not resolve; escalation_reason captured.
+    - abandoned: Session exited without resolution or explicit escalation.
+    """
+
+    __tablename__ = "l1_walk_sessions"
+    __table_args__ = (
+        CheckConstraint(
+            "ticket_kind IN ('psa', 'internal')",
+            name="ck_l1_walk_sessions_ticket_kind",
+        ),
+        CheckConstraint(
+            "session_kind IN ('flow', 'proposal', 'adhoc')",
+            name="ck_l1_walk_sessions_session_kind",
+        ),
+        CheckConstraint(
+            "status IN ('active', 'resolved', 'escalated', 'abandoned')",
+            name="ck_l1_walk_sessions_status",
+        ),
+        CheckConstraint(
+            "(session_kind = 'flow' AND flow_id IS NOT NULL AND flow_proposal_id IS NULL) "
+            "OR (session_kind = 'proposal' AND flow_proposal_id IS NOT NULL AND flow_id IS NULL) "
+            "OR (session_kind = 'adhoc' AND flow_id IS NULL AND flow_proposal_id IS NULL)",
+            name="ck_l1_walk_sessions_target_consistency",
+        ),
+    )
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    account_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("accounts.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+    created_by_user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("users.id", ondelete="RESTRICT"),
+        nullable=False,
+        index=True,
+    )
+
+    # ── Actor context ──
+    acting_as: Mapped[Optional[str]] = mapped_column(String(30), nullable=True)
+
+    # ── Ticket reference ──
+    ticket_id: Mapped[str] = mapped_column(String(64), nullable=False)
+    ticket_kind: Mapped[str] = mapped_column(String(10), nullable=False)
+
+    # ── Session kind + target ──
+    session_kind: Mapped[str] = mapped_column(String(20), nullable=False)
+    flow_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("trees.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+    flow_proposal_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True),
+        ForeignKey("flow_proposals.id", ondelete="SET NULL"),
+        nullable=True,
+    )
+
+    # ── Navigation state ──
+    current_node_id: Mapped[Optional[str]] = mapped_column(String(100), nullable=True)
+    walked_path: Mapped[list[dict[str, Any]]] = mapped_column(
+        JSONB(), nullable=False, server_default=sa_text("'[]'::jsonb"),
+    )
+    walk_notes: Mapped[list[dict[str, Any]]] = mapped_column(
+        JSONB(), nullable=False, server_default=sa_text("'[]'::jsonb"),
+    )
+
+    # ── Lifecycle ──
+    status: Mapped[str] = mapped_column(
+        String(20), nullable=False, server_default=sa_text("'active'"), index=True,
+    )
+
+    # ── Resolution ──
+    resolution_notes: Mapped[Optional[str]] = mapped_column(Text(), nullable=True)
+    helpful: Mapped[Optional[bool]] = mapped_column(Boolean(), nullable=True)
+
+    # ── Escalation ──
+    escalation_reason: Mapped[Optional[str]] = mapped_column(Text(), nullable=True)
+    escalation_reason_category: Mapped[Optional[str]] = mapped_column(
+        String(30), nullable=True,
+    )
+
+    # ── Timestamps ──
+    started_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
+    )
+    last_step_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        index=True,
+    )
+    resolved_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True), nullable=True,
+    )
+
+    # ── Relationships ──
+    account: Mapped["Account"] = relationship("Account")
+    created_by: Mapped["User"] = relationship("User", foreign_keys=[created_by_user_id])
+    flow: Mapped[Optional["Tree"]] = relationship("Tree")
+    flow_proposal: Mapped[Optional["FlowProposal"]] = relationship("FlowProposal")

backend/app/models/subscription.py

@@ -21,6 +21,7 @@ class Subscription(Base):
     billing_interval: Mapped[Optional[str]] = mapped_column(String(20), nullable=True)
     status: Mapped[str] = mapped_column(String(50), nullable=False, default="active")
     seat_limit: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
+    l1_seat_limit: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
     current_period_start: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
     current_period_end: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
     cancel_at_period_end: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)

backend/app/models/user.py

@@ -1,7 +1,7 @@
 import uuid
 from datetime import datetime, timezone
 from typing import Optional, TYPE_CHECKING
-from sqlalchemy import String, DateTime, ForeignKey, Boolean, CheckConstraint, Text, Integer
+from sqlalchemy import String, DateTime, ForeignKey, Boolean, CheckConstraint, Text, Integer, text
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 from sqlalchemy.dialects.postgresql import UUID
 from app.core.database import Base
@@ -22,7 +22,7 @@ class User(Base):
             name='ck_users_role_enum'
         ),
         CheckConstraint(
-            "account_role IN ('owner', 'admin', 'engineer', 'viewer')",
+            "account_role IN ('owner', 'admin', 'engineer', 'l1_tech', 'viewer')",
             name='ck_users_account_role_enum'
         ),
     )
@@ -50,6 +50,9 @@ class User(Base):
         index=True
     )
     account_role: Mapped[str] = mapped_column(String(50), nullable=False, default="engineer")
+    can_cover_l1: Mapped[bool] = mapped_column(
+        Boolean(), nullable=False, server_default=text('false')
+    )
 
     # Legacy team columns (kept for PR A coexistence)
     team_id: Mapped[Optional[uuid.UUID]] = mapped_column(

backend/app/schemas/account.py

@@ -27,7 +27,7 @@ class TransferOwnershipRequest(BaseModel):
 
 class AccountInviteCreate(BaseModel):
     email: str = Field(..., max_length=255)
-    role: str = Field("engineer", pattern="^(engineer|viewer)$")
+    role: str = Field("engineer", pattern="^(engineer|viewer|l1_tech)$")
     expires_in_days: Optional[int] = Field(None, ge=1, le=30)
 
 

backend/app/schemas/l1.py

@@ -0,0 +1,72 @@
+"""Pydantic schemas for the /l1/* endpoint surface."""
+from datetime import datetime
+from typing import Any, Literal, Optional
+from uuid import UUID
+
+from pydantic import BaseModel, Field
+
+
+class IntakeRequest(BaseModel):
+    problem_statement: str = Field(..., min_length=1)
+    customer_name: Optional[str] = None
+    customer_contact: Optional[str] = None
+    flow_id: Optional[UUID] = None
+
+
+class IntakeResponse(BaseModel):
+    session_id: UUID
+    session_kind: Literal["flow", "proposal", "adhoc"]
+    ticket_id: str
+    ticket_kind: Literal["psa", "internal"]
+
+
+class StepRequest(BaseModel):
+    node_id: str
+    question: str
+    answer: str
+    note: Optional[str] = None
+
+
+class NotesRequest(BaseModel):
+    notes: list[dict[str, Any]]
+
+
+class ResolveRequest(BaseModel):
+    helpful: bool
+    resolution_notes: str
+
+
+class EscalateRequest(BaseModel):
+    reason: Optional[str] = None
+    reason_category: str = Field(..., min_length=1)
+
+
+class EscalateWithoutWalkRequest(BaseModel):
+    problem_statement: str = Field(..., min_length=1)
+    customer_name: Optional[str] = None
+    customer_contact: Optional[str] = None
+    reason_category: str = Field(..., min_length=1)
+    reason: Optional[str] = None
+
+
+class WalkSessionResponse(BaseModel):
+    id: UUID
+    session_kind: str
+    flow_id: Optional[UUID]
+    flow_proposal_id: Optional[UUID]
+    current_node_id: Optional[str]
+    walked_path: list[dict[str, Any]]
+    walk_notes: list[dict[str, Any]]
+    status: str
+    started_at: datetime
+    last_step_at: datetime
+    resolved_at: Optional[datetime]
+
+
+class QueueRow(BaseModel):
+    ticket_id: str
+    ticket_kind: Literal["psa", "internal"]
+    problem_statement: Optional[str] = None
+    customer_name: Optional[str] = None
+    status: str
+    created_at: Optional[datetime] = None

backend/app/schemas/seat_enforcement.py

@@ -0,0 +1,18 @@
+from typing import Literal, Optional
+
+from pydantic import BaseModel
+
+
+Role = Literal['engineer', 'l1_tech']
+
+
+class SeatCheckResult(BaseModel):
+    available: bool
+    current: int
+    limit: Optional[int]   # None = unlimited
+    role: Role
+
+
+class SeatUsage(BaseModel):
+    engineer: SeatCheckResult
+    l1_tech: SeatCheckResult

backend/app/schemas/user.py

@@ -60,6 +60,7 @@ class UserResponse(UserBase):
     email_verified_at: Optional[datetime] = None
     onboarding_step_completed: Optional[int] = None
     onboarding_dismissed: bool = False
+    can_cover_l1: bool = False
 
     class Config:
         from_attributes = True
@@ -72,4 +73,8 @@ class RoleUpdate(BaseModel):
 class AccountRoleUpdate(BaseModel):
     # Ownership changes must go through the explicit transfer-ownership flow so
     # account.owner_id stays consistent with user.account_role.
-    account_role: str = Field(..., pattern="^(admin|engineer|viewer)$")
+    account_role: str = Field(..., pattern="^(admin|engineer|viewer|l1_tech)$")
+
+
+class CoverageUpdate(BaseModel):
+    can_cover_l1: bool

backend/app/services/internal_ticket_service.py

@@ -0,0 +1,90 @@
+"""CRUD + status transitions for internal_tickets (the no-PSA fallback ticket model)."""
+from datetime import datetime, timezone
+from typing import Optional
+from uuid import UUID
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.internal_ticket import InternalTicket
+
+
+async def create_ticket(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    created_by_user_id: UUID,
+    problem_statement: str,
+    customer_name: Optional[str] = None,
+    customer_contact: Optional[str] = None,
+) -> InternalTicket:
+    """Create a new internal ticket in 'open' status."""
+    ticket = InternalTicket(
+        account_id=account_id,
+        created_by_user_id=created_by_user_id,
+        problem_statement=problem_statement,
+        customer_name=customer_name,
+        customer_contact=customer_contact,
+    )
+    db.add(ticket)
+    await db.flush()
+    return ticket
+
+
+async def update_status(
+    db: AsyncSession,
+    *,
+    ticket_id: UUID,
+    status: str,
+    resolution_notes: Optional[str] = None,
+    assigned_user_id: Optional[UUID] = None,
+) -> InternalTicket:
+    """Transition a ticket to a new status. Sets resolved_at when status='resolved'."""
+    ticket = await db.get(InternalTicket, ticket_id)
+    if not ticket:
+        raise ValueError(f"InternalTicket {ticket_id} not found")
+    ticket.status = status
+    if status == 'resolved':
+        ticket.resolved_at = datetime.now(timezone.utc)
+        if resolution_notes is not None:
+            ticket.resolution_notes = resolution_notes
+    if assigned_user_id is not None:
+        ticket.assigned_user_id = assigned_user_id
+    await db.flush()
+    return ticket
+
+
+async def get_ticket(db: AsyncSession, *, ticket_id: UUID) -> Optional[InternalTicket]:
+    """Fetch a ticket by ID. Returns None if not found."""
+    return await db.get(InternalTicket, ticket_id)
+
+
+async def list_tickets_for_account(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    status: Optional[str] = None,
+    limit: int = 100,
+) -> list[InternalTicket]:
+    """List tickets for an account, optionally filtered by status, newest first."""
+    stmt = select(InternalTicket).where(InternalTicket.account_id == account_id)
+    if status:
+        stmt = stmt.where(InternalTicket.status == status)
+    stmt = stmt.order_by(InternalTicket.created_at.desc()).limit(limit)
+    result = await db.execute(stmt)
+    return list(result.scalars())
+
+
+async def promote_to_psa(
+    db: AsyncSession,
+    *,
+    ticket_id: UUID,
+    psa_ticket_id: str,
+) -> InternalTicket:
+    """Mark an internal ticket as promoted to PSA."""
+    ticket = await db.get(InternalTicket, ticket_id)
+    if not ticket:
+        raise ValueError(f"InternalTicket {ticket_id} not found")
+    ticket.psa_promoted_ticket_id = psa_ticket_id
+    await db.flush()
+    return ticket

backend/app/services/l1_session_cleanup.py

@@ -0,0 +1,49 @@
+"""Hourly cleanup job: flip stale active L1WalkSessions to 'abandoned'.
+
+Sessions with status='active' and last_step_at older than 24h are considered
+abandoned (L1 closed the browser, customer hung up, etc.). Flipping them
+removes them from the "Resume in progress" widget while preserving the row
+for audit/reporting.
+
+Run via APScheduler interval job, max_instances=1 (Lesson 1).
+"""
+import logging
+from datetime import datetime, timedelta, timezone
+
+from sqlalchemy import update
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.l1_walk_session import L1WalkSession
+
+
+logger = logging.getLogger(__name__)
+
+
+async def flip_stale_sessions(db: AsyncSession) -> int:
+    """Flip active sessions to 'abandoned' if last_step_at < now - 24h.
+
+    Returns the number of sessions flipped.
+    """
+    cutoff = datetime.now(timezone.utc) - timedelta(hours=24)
+    stmt = (
+        update(L1WalkSession)
+        .where(L1WalkSession.status == "active")
+        .where(L1WalkSession.last_step_at < cutoff)
+        .values(status="abandoned")
+    )
+    result = await db.execute(stmt)
+    await db.commit()
+    return result.rowcount or 0
+
+
+async def run_cleanup_job(session_factory) -> None:
+    """APScheduler entry point. Uses the admin session factory (no RLS context)."""
+    async with session_factory() as db:
+        try:
+            count = await flip_stale_sessions(db)
+            if count > 0:
+                logger.info(
+                    "l1_session_cleanup: flipped %d sessions to abandoned", count
+                )
+        except Exception:
+            logger.exception("l1_session_cleanup: error during run")

backend/app/services/l1_session_service.py

@@ -0,0 +1,321 @@
+"""L1 session lifecycle: start (flow/proposal/adhoc), step, notes, resolve, escalate.
+
+start_* functions live in T12; step/notes are T13; resolve/escalate are T14.
+"""
+import json
+from datetime import datetime, timezone
+from typing import Optional
+from uuid import UUID
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.audit import log_audit
+from app.models.flow_proposal import FlowProposal
+from app.models.l1_walk_session import L1WalkSession
+from app.models.user import User
+from app.services import internal_ticket_service
+
+
+def _resolve_acting_as(user: User) -> Optional[str]:
+    """An engineer (whether covering or not) gets tagged for audit when using L1 surface.
+
+    Returns 'l1_coverage' for engineers (only engineers WITH the coverage flag should
+    reach this code path — the require_l1_or_coverage dep gates that). For native
+    l1_tech users, returns None (no special tag — they ARE l1).
+    """
+    if user.account_role == "engineer":
+        return "l1_coverage"
+    return None
+
+
+async def start_flow_session(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    user: User,
+    flow_id: UUID,
+    ticket_id: str,
+    ticket_kind: str,  # 'psa' | 'internal'
+) -> L1WalkSession:
+    """Start a session walking an authored flow."""
+    session = L1WalkSession(
+        account_id=account_id,
+        created_by_user_id=user.id,
+        acting_as=_resolve_acting_as(user),
+        ticket_id=ticket_id,
+        ticket_kind=ticket_kind,
+        session_kind="flow",
+        flow_id=flow_id,
+    )
+    db.add(session)
+    await db.flush()
+    return session
+
+
+async def start_proposal_session(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    user: User,
+    flow_proposal_id: UUID,
+    ticket_id: str,
+    ticket_kind: str,
+) -> L1WalkSession:
+    """Start a session walking an AI-built FlowProposal."""
+    session = L1WalkSession(
+        account_id=account_id,
+        created_by_user_id=user.id,
+        acting_as=_resolve_acting_as(user),
+        ticket_id=ticket_id,
+        ticket_kind=ticket_kind,
+        session_kind="proposal",
+        flow_proposal_id=flow_proposal_id,
+    )
+    db.add(session)
+    await db.flush()
+    return session
+
+
+async def start_adhoc_session(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    user: User,
+    ticket_id: str,
+    ticket_kind: str,
+) -> L1WalkSession:
+    """Start an ad-hoc session with no tree (free-form note-taking only)."""
+    session = L1WalkSession(
+        account_id=account_id,
+        created_by_user_id=user.id,
+        acting_as=_resolve_acting_as(user),
+        ticket_id=ticket_id,
+        ticket_kind=ticket_kind,
+        session_kind="adhoc",
+    )
+    db.add(session)
+    await db.flush()
+    return session
+
+
+async def record_step(
+    db: AsyncSession,
+    *,
+    session_id: UUID,
+    node_id: str,
+    question: str,
+    answer: str,
+    note: Optional[str] = None,
+) -> L1WalkSession:
+    """Record an answered step in a tree walk. Appends to walked_path JSONB and
+    advances current_node_id. Raises ValueError on adhoc sessions or inactive
+    sessions. Updates last_step_at."""
+    session = await db.get(L1WalkSession, session_id)
+    if not session:
+        raise ValueError(f"L1WalkSession {session_id} not found")
+    if session.session_kind == "adhoc":
+        raise ValueError("Cannot record step on adhoc session — use update_notes")
+    if session.status != "active":
+        raise ValueError(f"Session {session_id} is not active (status={session.status})")
+    entry = {
+        "node_id": node_id,
+        "question": question,
+        "answer": answer,
+        "l1_note": note,
+    }
+    # JSONB requires assigning a new list — in-place mutation isn't tracked
+    session.walked_path = [*session.walked_path, entry]
+    session.current_node_id = node_id
+    session.last_step_at = datetime.now(timezone.utc)
+    await db.flush()
+    return session
+
+
+async def update_notes(
+    db: AsyncSession,
+    *,
+    session_id: UUID,
+    notes: list[dict],
+) -> L1WalkSession:
+    """Replace walk_notes on an active session. Used by adhoc walks for
+    debounced autosave. Raises ValueError if missing or inactive. Caps notes
+    payload at 256KB to prevent unbounded growth."""
+    session = await db.get(L1WalkSession, session_id)
+    if not session:
+        raise ValueError(f"L1WalkSession {session_id} not found")
+    if session.status != "active":
+        raise ValueError(f"Session {session_id} is not active (status={session.status})")
+    encoded_size = len(json.dumps(notes).encode("utf-8"))
+    if encoded_size > 256 * 1024:
+        raise ValueError("walk_notes exceeds 256KB cap — consider escalating")
+    session.walk_notes = notes
+    session.last_step_at = datetime.now(timezone.utc)
+    await db.flush()
+    return session
+
+
+async def resolve(
+    db: AsyncSession,
+    *,
+    session_id: UUID,
+    helpful: bool,
+    resolution_notes: str,
+) -> L1WalkSession:
+    """Close a session as resolved.
+
+    - Sets status='resolved', helpful, resolution_notes, resolved_at.
+    - On helpful=True AND session_kind='proposal': flips
+      flow_proposal.validated_by_outcome=True (one-bit aggregate signal).
+    - Closes the linked internal ticket (PSA close stubbed for Phase 2).
+    - Raises ValueError on missing or non-active session.
+    """
+    session = await db.get(L1WalkSession, session_id)
+    if not session:
+        raise ValueError(f"L1WalkSession {session_id} not found")
+    if session.status != "active":
+        raise ValueError(f"Session not active (status={session.status})")
+    now = datetime.now(timezone.utc)
+    session.status = "resolved"
+    session.helpful = helpful
+    session.resolution_notes = resolution_notes
+    session.resolved_at = now
+    session.last_step_at = now
+
+    if helpful and session.session_kind == "proposal" and session.flow_proposal_id:
+        proposal = await db.get(FlowProposal, session.flow_proposal_id)
+        if proposal:
+            proposal.validated_by_outcome = True
+
+    if session.ticket_kind == "internal":
+        await internal_ticket_service.update_status(
+            db,
+            ticket_id=UUID(session.ticket_id),
+            status="resolved",
+            resolution_notes=resolution_notes,
+        )
+    # PSA close deferred to Phase 2 — no-op for now
+
+    await log_audit(
+        db,
+        user_id=session.created_by_user_id,
+        action="l1.session.resolve",
+        resource_type="l1_walk_session",
+        resource_id=session.id,
+        details={
+            "session_kind": session.session_kind,
+            "helpful": helpful,
+            "ticket_id": session.ticket_id,
+            "ticket_kind": session.ticket_kind,
+        },
+        account_id=session.account_id,
+        acting_as=session.acting_as,
+    )
+    await db.flush()
+    return session
+
+
+async def escalate(
+    db: AsyncSession,
+    *,
+    session_id: UUID,
+    reason: str,
+    reason_category: str,
+) -> L1WalkSession:
+    """Escalate an active session to engineering.
+
+    - Sets status='escalated', escalation_reason, escalation_reason_category, resolved_at.
+    - Marks the linked internal ticket as escalated (PSA reassign deferred to Phase 2).
+    - Raises ValueError on missing or non-active session.
+    """
+    session = await db.get(L1WalkSession, session_id)
+    if not session:
+        raise ValueError(f"L1WalkSession {session_id} not found")
+    if session.status != "active":
+        raise ValueError(f"Session not active (status={session.status})")
+    now = datetime.now(timezone.utc)
+    session.status = "escalated"
+    session.escalation_reason = reason
+    session.escalation_reason_category = reason_category
+    session.resolved_at = now
+    session.last_step_at = now
+
+    if session.ticket_kind == "internal":
+        await internal_ticket_service.update_status(
+            db,
+            ticket_id=UUID(session.ticket_id),
+            status="escalated",
+        )
+    # PSA reassign deferred to Phase 2
+
+    await log_audit(
+        db,
+        user_id=session.created_by_user_id,
+        action="l1.session.escalate",
+        resource_type="l1_walk_session",
+        resource_id=session.id,
+        details={
+            "session_kind": session.session_kind,
+            "escalation_reason_category": reason_category,
+            "ticket_id": session.ticket_id,
+            "ticket_kind": session.ticket_kind,
+        },
+        account_id=session.account_id,
+        acting_as=session.acting_as,
+    )
+    await db.flush()
+    return session
+
+
+async def escalate_without_walk(
+    db: AsyncSession,
+    *,
+    account_id: UUID,
+    user: User,
+    ticket_id: str,
+    ticket_kind: str,
+    reason_category: str,
+    reason: Optional[str] = None,
+) -> L1WalkSession:
+    """Create an immediately-escalated session with no walked_path.
+
+    Used from the BuildAbortedNoKB screen (no KB content available to walk a
+    tree). Captures the call as an audit record + escalates the ticket without
+    requiring a walker session in between.
+    """
+    now = datetime.now(timezone.utc)
+    session = L1WalkSession(
+        account_id=account_id,
+        created_by_user_id=user.id,
+        acting_as=_resolve_acting_as(user),
+        ticket_id=ticket_id,
+        ticket_kind=ticket_kind,
+        session_kind="adhoc",
+        status="escalated",
+        escalation_reason=reason,
+        escalation_reason_category=reason_category,
+        resolved_at=now,
+        last_step_at=now,
+    )
+    db.add(session)
+    if ticket_kind == "internal":
+        await internal_ticket_service.update_status(
+            db,
+            ticket_id=UUID(ticket_id),
+            status="escalated",
+        )
+    await db.flush()  # flush first so session.id is populated
+    await log_audit(
+        db,
+        user_id=session.created_by_user_id,
+        action="l1.session.escalate_no_walk",
+        resource_type="l1_walk_session",
+        resource_id=session.id,
+        details={
+            "escalation_reason_category": reason_category,
+            "ticket_id": ticket_id,
+            "ticket_kind": ticket_kind,
+        },
+        account_id=session.account_id,
+        acting_as=session.acting_as,
+    )
+    return session

backend/app/services/seat_enforcement.py

@@ -0,0 +1,63 @@
+from typing import Literal
+
+from sqlalchemy import func, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.account import Account
+from app.models.subscription import Subscription
+from app.models.user import User
+from app.schemas.seat_enforcement import SeatCheckResult
+
+
+Role = Literal['engineer', 'l1_tech']
+
+
+def _limit_for_role(subscription: Subscription, role: Role) -> int | None:
+    if role == 'engineer':
+        return subscription.seat_limit
+    if role == 'l1_tech':
+        return subscription.l1_seat_limit
+    raise ValueError(f"Unknown role: {role}")
+
+
+async def check_seat_available(
+    account: Account,
+    subscription: Subscription,
+    role: Role,
+    db: AsyncSession,
+) -> SeatCheckResult:
+    """
+    Count active users with the given role in the account, compare against
+    the role-specific seat limit on the subscription. Returns availability.
+
+    None limit = unlimited (returns available=True).
+    """
+    limit = _limit_for_role(subscription, role)
+
+    stmt = (
+        select(func.count(User.id))
+        .where(User.account_id == account.id)
+        .where(User.account_role == role)
+        .where(User.is_active.is_(True))
+    )
+    current = (await db.execute(stmt)).scalar_one()
+
+    if limit is None:
+        return SeatCheckResult(available=True, current=current, limit=None, role=role)
+    return SeatCheckResult(
+        available=current < limit,
+        current=current,
+        limit=limit,
+        role=role,
+    )
+
+
+async def get_seat_usage(
+    account: Account,
+    subscription: Subscription,
+    db: AsyncSession,
+) -> tuple[SeatCheckResult, SeatCheckResult]:
+    """Return (engineer, l1_tech) seat-usage tuple for the seat-counter widget."""
+    eng = await check_seat_available(account, subscription, 'engineer', db)
+    l1 = await check_seat_available(account, subscription, 'l1_tech', db)
+    return eng, l1