feat(astuce): ajout colonnes categorie/tags/mois + migration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/migrate.py

@@ -32,6 +32,11 @@ EXPECTED_COLUMNS: dict[str, list[tuple[str, str, str | None]]] = {
         ("identified_confidence", "REAL", None),
         ("identified_source", "TEXT", None),
     ],
+    "astuce": [
+        ("categorie", "TEXT", None),
+        ("tags", "TEXT", None),
+        ("mois", "TEXT", None),
+    ],
 }