refactor: improve handling of endpoints metadata to lazy load them

chore: fix metadata init

Author: vemonet

.github/workflows/deploy.yml

@@ -2,6 +2,8 @@ name: Publish tutorial to GitHub Pages
 on:
   push:
     branches: ["main"]
+    paths:
+      - 'tutorial/**'
   workflow_dispatch:
 
 permissions:

src/sparql_llm/utils.py

@@ -218,6 +218,7 @@ def _ensure_loaded(self) -> None:
                         f"💾 Loaded endpoints metadata from {ENDPOINTS_METADATA_FILE.resolve()} "
                         f"for {len(self._void_dict)} endpoints"
                     )
+                    self._initialized = True
                     return
         except Exception as e:
             logger.debug(f"Could not load metadata from {ENDPOINTS_METADATA_FILE}: {e}")