chore: initial project setup with backend, frontend, and infrastructure

Add complete NexaPantry application structure including:
- Docker Compose configuration with PostgreSQL, Redis, FastAPI backend, worker, frontend and Caddy
- Environment configuration template with database, auth, and service settings
- GitHub Actions CI workflow for backend/frontend linting, testing, auditing and Docker builds
- AGPL-3.0 license and comprehensive README with setup, development, and security documentation
- Backend

backend/app/services/audit.py

@@ -0,0 +1,16 @@
+from sqlalchemy.orm import Session
+
+from app.models.entities import AuditLog, User
+
+
+def audit(db: Session, actor: User | None, action: str, target_type: str | None = None, target_id: str | None = None, metadata: dict | None = None) -> None:
+    db.add(
+        AuditLog(
+            actor_user_id=actor.id if actor else None,
+            action=action,
+            target_type=target_type,
+            target_id=target_id,
+            metadata_json=metadata or {},
+        )
+    )
+