feat: add --use-existing-index option to google_history_reader_leann.py

- Allow using existing index without rebuilding
- Useful for testing pre-built indices

examples/google_history_reader_leann.py

@@ -298,6 +298,11 @@ async def main():
         choices=["sentence-transformers", "openai", "mlx"],
         help="The embedding backend mode",
     )
+    parser.add_argument(
+        "--use-existing-index",
+        action="store_true",
+        help="Use existing index without rebuilding",
+    )
 
     args = parser.parse_args()
 
@@ -308,6 +313,14 @@ async def main():
     print(f"Index directory: {INDEX_DIR}")
     print(f"Max entries: {args.max_entries}")
 
+    if args.use_existing_index:
+        # Use existing index without rebuilding
+        if not Path(INDEX_PATH).exists():
+            print(f"Error: Index file not found at {INDEX_PATH}")
+            return
+        print(f"Using existing index at {INDEX_PATH}")
+        index_path = INDEX_PATH
+    else:
         # Find Chrome profile directories
         from history_data.history import ChromeHistoryReader