debug: add logging to auth cookie handling

Add debug logging to understand why /auth/me succeeds but
/users/me/config fails with 401.

apps/api/src/auth/dependencies.py

@@ -18,8 +18,14 @@ async def get_db_session():
 async def get_current_user_id(
     session_cookie: Annotated[str | None, Cookie()] = None,
 ) -> uuid.UUID:
+    import logging
+    logger = logging.getLogger(__name__)
+    
     if not session_cookie:
+        logger.warning("No session cookie found in request")
         raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="missing session")
+    
+    logger.debug("Session cookie found: %s...", session_cookie[:20])
 
     settings = Settings()
     try: