feat: add cockpit triage backend foundation (Phase 1)

- Migration 071: add client_name, asset_name, issue_category,
  triage_hypothesis, evidence_items columns to ai_sessions
- TriageUpdate schema for AI-inferred header updates in chat responses
- QuestionItem.options field for quick-reply buttons
- PATCH /ai-sessions/{id}/triage endpoint for manual header edits
- POST /ai-sessions/{id}/handoff-draft streaming endpoint for conclude modal
- Structured handoff fields (root_cause, steps_taken, recommendations)
  on resolve/escalate requests, passed through to ResolutionOutputGenerator
- Triage fields exposed in AISessionDetail response for session resume

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/api/endpoints/ai_sessions.py

@@ -49,6 +49,8 @@ from app.schemas.ai_session import (
     ChatMessageRequest,
     ChatMessageResponse,
     SaveTaskLaneRequest,
+    TriagePatchRequest,
+    TriagePatchResponse,
 )
 from app.services import flowpilot_engine
 from app.services import unified_chat_service
@@ -120,6 +122,11 @@ def _build_session_detail(session: AISession) -> AISessionDetail:
         pending_task_lane=session.pending_task_lane,
         is_branching=getattr(session, 'is_branching', False),
         active_branch_id=str(session.active_branch_id) if getattr(session, 'active_branch_id', None) else None,
+        client_name=getattr(session, 'client_name', None),
+        asset_name=getattr(session, 'asset_name', None),
+        issue_category=getattr(session, 'issue_category', None),
+        triage_hypothesis=getattr(session, 'triage_hypothesis', None),
+        evidence_items=getattr(session, 'evidence_items', None),
     )
 
 
@@ -442,7 +449,12 @@ async def resolve_session(
         try:
             from app.services.resolution_output_generator import ResolutionOutputGenerator
             gen = ResolutionOutputGenerator(db)
-            await gen.generate_all(session_id)
+            await gen.generate_all(
+                session_id,
+                root_cause=data.root_cause,
+                steps_taken=data.steps_taken,
+                recommendations=data.recommendations,
+            )
         except Exception:
             logger.exception(f"Failed to generate resolution outputs for session {session_id}")
 
@@ -540,6 +552,122 @@ async def save_task_lane(
     await db.commit()
 
 
+# ── Triage Metadata ──
+
+@router.patch("/{session_id}/triage", response_model=TriagePatchResponse)
+@limiter.limit("30/minute")
+async def update_triage(
+    request: Request,
+    session_id: UUID,
+    body: TriagePatchRequest,
+    current_user: Annotated[User, Depends(get_current_active_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+    _: None = Depends(require_engineer_or_admin),
+):
+    """Update triage metadata on a session (incident header fields)."""
+    session = await db.get(AISession, session_id)
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    if session.user_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not your session")
+
+    patch_data = body.model_dump(exclude_unset=True)
+    for field, value in patch_data.items():
+        setattr(session, field, value)
+
+    await db.commit()
+    await db.refresh(session)
+
+    return TriagePatchResponse(
+        id=session.id,
+        client_name=session.client_name,
+        asset_name=session.asset_name,
+        issue_category=session.issue_category,
+        triage_hypothesis=session.triage_hypothesis,
+        evidence_items=session.evidence_items,
+    )
+
+
+# ── Handoff Draft ──
+
+@router.post("/{session_id}/handoff-draft")
+@limiter.limit("10/minute")
+async def handoff_draft(
+    request: Request,
+    session_id: UUID,
+    current_user: Annotated[User, Depends(get_current_active_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+    _: None = Depends(require_engineer_or_admin),
+):
+    """Stream a structured handoff draft for the conclude modal."""
+    from fastapi.responses import StreamingResponse
+    from app.services.assistant_chat_service import _call_ai
+
+    session = await db.get(AISession, session_id)
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    if session.user_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not your session")
+
+    # Build context from session data
+    context_parts = [
+        f"Problem: {session.problem_summary or 'Unknown'}",
+        f"Domain: {session.problem_domain or 'Unknown'}",
+        f"Client: {session.client_name or 'Unknown'}",
+        f"Asset: {session.asset_name or 'Unknown'}",
+        f"Hypothesis: {session.triage_hypothesis or 'None'}",
+    ]
+
+    if session.evidence_items:
+        context_parts.append("\nEvidence collected:")
+        for item in session.evidence_items:
+            status_icon = {"confirmed": "✓", "ruled_out": "✗", "pending": "?"}.get(item.get("status", ""), "?")
+            context_parts.append(f"  {status_icon} {item.get('text', '')}")
+
+    # Include task lane steps if available
+    if session.pending_task_lane:
+        actions = session.pending_task_lane.get("actions", [])
+        if actions:
+            context_parts.append("\nSteps taken:")
+            for a in actions:
+                context_parts.append(f"  - {a.get('label', '')}")
+
+    # Include last 20 conversation messages
+    msgs = session.conversation_messages or []
+    if msgs:
+        context_parts.append("\nRecent conversation:")
+        for msg in msgs[-20:]:
+            role = msg.get("role", "unknown")
+            content = msg.get("content", "")[:300]
+            context_parts.append(f"  [{role}]: {content}")
+
+    context = "\n".join(context_parts)
+
+    prompt = (
+        "Generate a structured handoff summary for this troubleshooting session.\n"
+        "Return ONLY valid JSON with exactly these four fields:\n"
+        '{"root_cause": "...", "resolution": "...", "steps_taken": ["step1", "step2"], "recommendations": "..."}\n\n'
+        f"Session context:\n{context}"
+    )
+
+    async def generate():
+        try:
+            content, _, _ = await _call_ai(
+                system_base="You are a concise technical documentation assistant for MSP teams. Return only JSON.",
+                rag_context="",
+                history=[],
+                new_message=prompt,
+                max_tokens=1024,
+            )
+            yield f"data: {content}\n\n"
+        except Exception as e:
+            logger.exception(f"Handoff draft generation failed for session {session_id}")
+            import json
+            yield f"data: {json.dumps({'error': str(e)})}\n\n"
+
+    return StreamingResponse(generate(), media_type="text/event-stream")
+
+
 # ── Resume ──
 
 @router.post("/{session_id}/resume", status_code=204)