feat(auth): implement GET /auth/me for NPM forward auth

Add endpoint to get current user profile from NPM forward auth headers.
Enables web authentication flow where NPM handles Authentik login.

- Read X-authentik-* headers set by NPM forward auth
- Auto-create user if not in database (first login via web)
- Sync roles from current Authentik groups
- Add get_user_by_email and get_user_by_authentik_id helpers

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/auth/controller.py

@@ -13,6 +13,7 @@ from src.logging_config import get_logger
 from src.db import get_async_session
 from src.auth.schemas import AuthSyncRequest, AuthSyncResponse, UsersListResponse, BulkSyncResultSchema, GroupsListResponse
 from src.auth.service import AuthService
+from src.auth.oidc import get_forward_auth_user
 
 logger = get_logger(__name__)
 
@@ -222,21 +223,83 @@ class AuthController(BaseController):
             responses={
                 200: {"description": "User profile"},
                 401: {"description": "Not authenticated"},
+                404: {"description": "User not found in database"},
             },
         )
         async def get_me(
+            forward_auth_user: Optional[dict] = Depends(get_forward_auth_user),
             session: AsyncSession = Depends(get_async_session),
-        ) -> JSONResponse:
+        ) -> AuthSyncResponse:
             """
             Get the current authenticated user's profile
 
-            Note: This endpoint requires a valid session or API key.
-            For now, returns 501 Not Implemented until session management is added.
+            Authentication is handled by NPM forward auth with Authentik.
+            The proxy sets X-authentik-* headers which this endpoint reads.
+
+            For internal/LAN access (no forward auth headers), returns 401.
+            Use POST /auth/sync with an OIDC token for mobile app authentication.
             """
-            # TODO: Implement with get_current_user dependency
-            raise HTTPException(
-                status_code=501,
-                detail="Not implemented - use /auth/sync with access token",
+            # Require forward auth for this endpoint
+            if forward_auth_user is None:
+                raise HTTPException(
+                    status_code=401,
+                    detail="Authentication required - access via authenticated proxy or use /auth/sync",
+                )
+
+            service = AuthService(session)
+
+            # Try to find user by Authentik UID first, then by email
+            user = None
+            uid = forward_auth_user.get("uid")
+            if uid:
+                try:
+                    import uuid
+                    authentik_id = uuid.UUID(uid)
+                    user = await service.get_user_by_authentik_id(authentik_id)
+                except (ValueError, TypeError):
+                    pass  # Invalid UUID, try email
+
+            if user is None:
+                email = forward_auth_user.get("email")
+                if email:
+                    user = await service.get_user_by_email(email)
+
+            if user is None:
+                # User authenticated with Authentik but not synced to database yet
+                # This can happen on first login via web
+                logger.info(f"User {forward_auth_user.get('email')} not found, creating from forward auth")
+
+                # Create user from forward auth headers
+                from src.auth.schemas import TokenInfoSchema
+                token_info = TokenInfoSchema(
+                    sub=forward_auth_user.get("uid", ""),
+                    email=forward_auth_user.get("email", ""),
+                    name=forward_auth_user.get("name"),
+                    groups=forward_auth_user.get("groups", []),
+                )
+
+                try:
+                    user, _ = await service.sync_user(token_info)
+                    await service.sync_roles(user, token_info.groups)
+                    await session.commit()
+                    await session.refresh(user, ["preferences", "roles"])
+                except Exception as e:
+                    logger.error(f"Failed to create user from forward auth: {e}")
+                    raise HTTPException(
+                        status_code=500,
+                        detail="Failed to create user profile",
+                    )
+
+            # Sync roles from current groups (in case they changed)
+            groups = forward_auth_user.get("groups", [])
+            roles = await service.sync_roles(user, groups)
+            await session.commit()
+
+            return AuthSyncResponse(
+                user=service.user_to_schema(user),
+                roles=service.roles_to_schema(roles),
+                preferences=service.preferences_to_schema(user.preferences),
+                is_new_user=False,
             )
 
         return router

src/auth/service.py

@@ -86,6 +86,42 @@ class AuthService:
             logger.error(f"Authentik userinfo request error: {e}")
             raise ValueError("Authentication service unavailable")
 
+    async def get_user_by_email(self, email: str) -> Optional[User]:
+        """
+        Get user by email address
+
+        Args:
+            email: User email address
+
+        Returns:
+            User if found, None otherwise
+        """
+        stmt = (
+            select(User)
+            .options(selectinload(User.roles), selectinload(User.preferences))
+            .where(User.email == email)
+        )
+        result = await self.session.execute(stmt)
+        return result.scalar_one_or_none()
+
+    async def get_user_by_authentik_id(self, authentik_id: uuid.UUID) -> Optional[User]:
+        """
+        Get user by Authentik UUID
+
+        Args:
+            authentik_id: Authentik user UUID
+
+        Returns:
+            User if found, None otherwise
+        """
+        stmt = (
+            select(User)
+            .options(selectinload(User.roles), selectinload(User.preferences))
+            .where(User.authentik_id == authentik_id)
+        )
+        result = await self.session.execute(stmt)
+        return result.scalar_one_or_none()
+
     async def sync_user(self, token_info: TokenInfoSchema) -> tuple[User, bool]:
         """
         Create or update user from OIDC token info