feat: Add file name display in WebUI

Backend:
- Add file_path field to DocStatusResponse
- Update document status response creation

Frontend:
- Remove metadata column
- Improve filename display with truncation and tooltips
- Add show/hide filename toggle with proper styling
- Update translations for all supported languages"

lightrag_webui/src/locales/en.json

@@ -83,7 +83,12 @@
         "loadFailed": "Failed to load documents\n{{error}}",
         "scanFailed": "Failed to scan documents\n{{error}}",
         "scanProgressFailed": "Failed to get scan progress\n{{error}}"
-      }
+      },
+      "fileNameLabel": "File Name",
+      "showButton": "Show",
+      "hideButton": "Hide",
+      "showFileNameTooltip": "Show file name",
+      "hideFileNameTooltip": "Hide file name"
     }
   },
   "graphPanel": {