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/settings.py

@@ -21,7 +21,7 @@ from app.core.database import get_db
 from app.exceptions import ConfirmationRequiredException, ResourceNotFoundException
 from app.services.admin_audit_service import admin_audit_service
 from app.services.admin_settings_service import admin_settings_service
-from models.database.user import User
+from models.schema.auth import UserContext
 from models.schema.admin import (
     AdminSettingCreate,
     AdminSettingDefaultResponse,
@@ -42,7 +42,7 @@ def get_all_settings(
     category: str | None = Query(None, description="Filter by category"),
     is_public: bool | None = Query(None, description="Filter by public flag"),
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Get all platform settings.
@@ -60,7 +60,7 @@ def get_all_settings(
 @router.get("/categories")
 def get_setting_categories(
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """Get list of all setting categories."""
     # This could be enhanced to return counts per category
@@ -81,7 +81,7 @@ def get_setting(
     key: str,
     default: str | None = Query(None, description="Default value if setting not found"),
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ) -> AdminSettingResponse | AdminSettingDefaultResponse:
     """Get specific setting by key.
 
@@ -103,7 +103,7 @@ def get_setting(
 def create_setting(
     setting_data: AdminSettingCreate,
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Create new platform setting.
@@ -136,7 +136,7 @@ def update_setting(
     key: str,
     update_data: AdminSettingUpdate,
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """Update existing setting value."""
     old_value = admin_settings_service.get_setting_value(db, key)
@@ -163,7 +163,7 @@ def update_setting(
 def upsert_setting(
     setting_data: AdminSettingCreate,
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Create or update setting (upsert).
@@ -196,7 +196,7 @@ def upsert_setting(
 @router.get("/display/rows-per-page", response_model=RowsPerPageResponse)
 def get_rows_per_page(
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ) -> RowsPerPageResponse:
     """Get the platform-wide rows per page setting."""
     value = admin_settings_service.get_setting_value(db, "rows_per_page", default="20")
@@ -207,7 +207,7 @@ def get_rows_per_page(
 def set_rows_per_page(
     rows: int = Query(..., ge=10, le=100, description="Rows per page (10-100)"),
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ) -> RowsPerPageUpdateResponse:
     """
     Set the platform-wide rows per page setting.
@@ -268,7 +268,7 @@ def delete_setting(
     key: str,
     confirm: bool = Query(False, description="Must be true to confirm deletion"),
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Delete platform setting.
@@ -473,7 +473,7 @@ class TestEmailResponse(BaseModel):
 @router.get("/email/status", response_model=EmailStatusResponse)
 def get_email_status(
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ) -> EmailStatusResponse:
     """
     Get platform email configuration status.
@@ -519,7 +519,7 @@ def get_email_status(
 def update_email_settings(
     settings_update: EmailSettingsUpdate,
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Update platform email settings.
@@ -607,7 +607,7 @@ def update_email_settings(
 @router.delete("/email/settings")
 def reset_email_settings(
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """
     Reset email settings to use .env values.
@@ -646,7 +646,7 @@ def reset_email_settings(
 def send_test_email(
     request: TestEmailRequest,
     db: Session = Depends(get_db),
-    current_admin: User = Depends(get_current_admin_api),
+    current_admin: UserContext = Depends(get_current_admin_api),
 ) -> TestEmailResponse:
     """
     Send a test email using the platform email configuration.