chore: mise à jour index FAISS (+15 référentiels ATIH) et cache ollama

- Index FAISS ref/proc enrichis avec 15 nouveaux documents ATIH/DGOS
- Métadonnées FAISS refactorisées (metadata_ref, metadata_proc séparés)
- Référentiels utilisateur ajoutés (5 docs)
- Nettoyage cache ollama (suppression backup gemma3)

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

data/referentiels/user/index.json

@@ -298,5 +298,25 @@
     "date_added": "2026-03-07T15:28:28.144893",
     "status": "indexed",
     "chunks_count": 193
+  },
+  {
+    "id": "00634c74a33e",
+    "filename": "doc.txt",
+    "stored_name": "user/00634c74a33e_doc.txt",
+    "extension": ".txt",
+    "size_bytes": 12,
+    "date_added": "2026-03-07T18:38:07.579496",
+    "status": "uploaded",
+    "chunks_count": 0
+  },
+  {
+    "id": "659540ed9c42",
+    "filename": "doc.txt",
+    "stored_name": "user/659540ed9c42_doc.txt",
+    "extension": ".txt",
+    "size_bytes": 12,
+    "date_added": "2026-03-07T21:20:31.742855",
+    "status": "uploaded",
+    "chunks_count": 0
   }
 ]