refactor(api): introduce UserContext schema for API dependency injection

Replace direct User database model imports in API endpoints with UserContext
schema, following the architecture principle that API routes should not import
database models directly.

Changes:
- Create UserContext schema in models/schema/auth.py with from_user() factory
- Update app/api/deps.py to return UserContext from all auth dependencies
- Add _get_user_model() helper for functions needing User model access
- Update 58 API endpoint files to use UserContext instead of User
- Add noqa comments for 4 legitimate edge cases (enums, internal helpers)

Architecture validation: 0 errors (down from 61), 11 warnings remain

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/api/v1/admin/tests.py

@@ -11,7 +11,7 @@ from app.api.deps import get_current_admin_api
 from app.core.database import get_db
 from app.services.test_runner_service import test_runner_service
 from app.tasks.test_runner_tasks import execute_test_run
-from models.database.user import User
+from models.schema.auth import UserContext
 
 router = APIRouter()
 
@@ -108,7 +108,7 @@ async def run_tests(
     background_tasks: BackgroundTasks,
     request: RunTestsRequest | None = None,
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Start a pytest run in the background
@@ -168,7 +168,7 @@ async def run_tests(
 async def list_runs(
     limit: int = Query(20, ge=1, le=100, description="Number of runs to return"),
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get test run history
@@ -205,7 +205,7 @@ async def list_runs(
 async def get_run(
     run_id: int,
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get a specific test run
@@ -245,7 +245,7 @@ async def get_run_results(
         None, description="Filter by outcome (passed, failed, error, skipped)"
     ),
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get test results for a specific run
@@ -272,7 +272,7 @@ async def get_run_results(
 async def get_run_failures(
     run_id: int,
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get failed tests from a specific run
@@ -298,7 +298,7 @@ async def get_run_failures(
 @router.get("/stats", response_model=TestDashboardStatsResponse)
 async def get_dashboard_stats(
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get dashboard statistics
@@ -317,7 +317,7 @@ async def get_dashboard_stats(
 @router.post("/collect")
 async def collect_tests(
     db: Session = Depends(get_db),
-    current_user: User = Depends(get_current_admin_api),
+    current_user: UserContext = Depends(get_current_admin_api),
 ):
     """
     Collect test information without running tests