Fix list performance for large buckets: delimiter-aware shallow listing, cache TTL increase, UI delimiter streaming. header badge shows total bucket objects, fix status bar text concatenation

app/__init__.py

@@ -115,7 +115,7 @@ def create_app(
 
     storage = ObjectStorage(
         Path(app.config["STORAGE_ROOT"]),
-        cache_ttl=app.config.get("OBJECT_CACHE_TTL", 5),
+        cache_ttl=app.config.get("OBJECT_CACHE_TTL", 60),
         object_cache_max_size=app.config.get("OBJECT_CACHE_MAX_SIZE", 100),
         bucket_config_cache_ttl=app.config.get("BUCKET_CONFIG_CACHE_TTL_SECONDS", 30.0),
         object_key_max_length_bytes=app.config.get("OBJECT_KEY_MAX_LENGTH_BYTES", 1024),