Add reload endpoint response model for per-vault indexing statistics

backend/main.py

@@ -137,6 +137,12 @@ class TreeSearchResponse(BaseModel):
     results: List[TreeSearchResult]
 
 
+class ReloadResponse(BaseModel):
+    """Index reload confirmation with per-vault stats."""
+    status: str
+    vaults: Dict[str, Any]
+
+
 class HealthResponse(BaseModel):
     """Application health status."""
     status: str