fix: Add numpy and pillow to CI build validation step

The backend validation step was failing because numpy is required for
importing backend.services.face_service, which is imported at module level.
Adding numpy and pillow to the pip install command in the build job to
fix the ModuleNotFoundError.

.gitea/workflows/ci.yml

@@ -426,7 +426,9 @@ jobs:
           python3 -m venv /tmp/backend-venv
           
           # Use venv's pip and python directly (avoids shell activation issues)
-          /tmp/backend-venv/bin/pip install --no-cache-dir fastapi uvicorn pydantic sqlalchemy psycopg2-binary redis rq python-jose python-multipart python-dotenv bcrypt
+          # Install core dependencies including numpy and pillow (needed for module-level imports)
+          # Skip heavy ML dependencies (tensorflow, deepface, opencv) for faster builds
+          /tmp/backend-venv/bin/pip install --no-cache-dir fastapi uvicorn pydantic sqlalchemy psycopg2-binary redis rq python-jose python-multipart python-dotenv bcrypt numpy pillow
           
           # Set environment variables for validation
           export PYTHONPATH=$(pwd)