feat: add GET /auth/me/feature-flags resolution endpoint

Resolves feature flags for the current user using:
account override > plan default > false

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/api/endpoints/auth.py

@@ -26,6 +26,7 @@ from app.models.refresh_token import RefreshToken
 from app.models.account import Account
 from app.models.subscription import Subscription
 from app.models.account_invite import AccountInvite
+from app.models.feature_flag import FeatureFlag, PlanFeatureDefault, AccountFeatureOverride
 from app.schemas.user import UserCreate, UserResponse, UserLogin, UserUpdate
 from app.schemas.token import Token
 from app.schemas.auth_password import (
@@ -718,3 +719,59 @@ async def verify_email(
     await db.commit()
 
     return {"message": "Email verified successfully"}
+
+
+@router.get("/me/feature-flags")
+async def get_my_feature_flags(
+    current_user: Annotated[User, Depends(get_current_active_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+) -> dict[str, bool]:
+    """Resolve feature flags for the current user's account and plan."""
+    plan = "free"
+    if current_user.account_id:
+        sub_result = await db.execute(
+            select(Subscription).where(
+                Subscription.account_id == current_user.account_id,
+                Subscription.status.in_(["active", "trialing"]),
+            )
+        )
+        sub = sub_result.scalar_one_or_none()
+        if sub:
+            plan = sub.plan
+
+    flags_result = await db.execute(select(FeatureFlag))
+    flags = flags_result.scalars().all()
+
+    if not flags:
+        return {}
+
+    flag_ids = [f.id for f in flags]
+
+    defaults_result = await db.execute(
+        select(PlanFeatureDefault).where(
+            PlanFeatureDefault.flag_id.in_(flag_ids),
+            PlanFeatureDefault.plan == plan,
+        )
+    )
+    plan_defaults = {d.flag_id: d.enabled for d in defaults_result.scalars().all()}
+
+    overrides: dict = {}
+    if current_user.account_id:
+        overrides_result = await db.execute(
+            select(AccountFeatureOverride).where(
+                AccountFeatureOverride.flag_id.in_(flag_ids),
+                AccountFeatureOverride.account_id == current_user.account_id,
+            )
+        )
+        overrides = {o.flag_id: o.enabled for o in overrides_result.scalars().all()}
+
+    resolved = {}
+    for flag in flags:
+        if flag.id in overrides:
+            resolved[flag.flag_key] = overrides[flag.id]
+        elif flag.id in plan_defaults:
+            resolved[flag.flag_key] = plan_defaults[flag.id]
+        else:
+            resolved[flag.flag_key] = False
+
+    return resolved