refactor: enforce strict architecture rules and add Pydantic response models

- Update architecture rules to be stricter (API-003 now blocks ALL exception
  raising in endpoints, not just HTTPException)
- Update get_current_vendor_api dependency to guarantee token_vendor_id presence
- Remove redundant _get_vendor_from_token helpers from all vendor API files
- Move vendor access validation to service layer methods
- Add Pydantic response models for media, notification, and payment endpoints
- Add get_active_vendor_by_code service method for public vendor lookup
- Add get_import_job_for_vendor service method with vendor validation
- Update validation script to detect exception raising patterns in endpoints

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/api/v1/vendor/analytics.py

@@ -2,7 +2,8 @@
 """
 Vendor analytics and reporting endpoints.
 
-Vendor Context: Uses token_vendor_id from JWT token (authenticated vendor API pattern)
+Vendor Context: Uses token_vendor_id from JWT token (authenticated vendor API pattern).
+The get_current_vendor_api dependency guarantees token_vendor_id is present.
 """
 
 import logging
@@ -12,7 +13,6 @@ from sqlalchemy.orm import Session
 
 from app.api.deps import get_current_vendor_api
 from app.core.database import get_db
-from app.exceptions import InvalidTokenException
 from app.services.stats_service import stats_service
 from models.database.user import User
 
@@ -20,13 +20,6 @@ router = APIRouter(prefix="/analytics")
 logger = logging.getLogger(__name__)
 
 
-def _get_vendor_id_from_token(current_user: User) -> int:
-    """Helper to get vendor_id from JWT token."""
-    if not hasattr(current_user, "token_vendor_id"):
-        raise InvalidTokenException("Token missing vendor information. Please login again.")
-    return current_user.token_vendor_id
-
-
 @router.get("")
 def get_vendor_analytics(
     period: str = Query("30d", description="Time period: 7d, 30d, 90d, 1y"),
@@ -34,5 +27,4 @@ def get_vendor_analytics(
     db: Session = Depends(get_db),
 ):
     """Get vendor analytics data for specified time period."""
-    vendor_id = _get_vendor_id_from_token(current_user)
-    return stats_service.get_vendor_analytics(db, vendor_id, period)
+    return stats_service.get_vendor_analytics(db, current_user.token_vendor_id, period)