feat: JWT auth, user management, audit logging system

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

backend/app/middleware/auth.py

@@ -0,0 +1,27 @@
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.services.auth_service import decode_access_token, get_user_by_id
+
+security = HTTPBearer()
+
+
+async def require_auth(
+    credentials: HTTPAuthorizationCredentials = Depends(security),
+    db: AsyncSession = Depends(get_db),
+):
+    payload = decode_access_token(credentials.credentials)
+    user = await get_user_by_id(db, payload["sub"])
+    if not user or not user.is_active:
+        raise HTTPException(status_code=401, detail="Invalid or inactive user")
+    return user
+
+
+def require_role(*roles: str):
+    async def role_check(user=Depends(require_auth)):
+        if user.role.value not in roles:
+            raise HTTPException(status_code=403, detail="Insufficient permissions")
+        return user
+    return role_check