feat(geodata): add standard source presets (#6504)

* feat(geodata): add standard source presets

Expose the existing geofile allowlist to the Geodata editor so administrators can configure the supported scheduled downloads without copying URLs manually

Tested with npm run test, npm run lint, npm run typecheck, npm run format:check, and go test ./internal/web/service ./internal/web/controller -run '^(TestStandardGeodataSources|TestGeodata)' -count=1

Assisted-by: OpenCode:openai/gpt-5.6-terra (mostly)

* fix(geodata): preserve custom source entries

Add missing standard sources instead of replacing existing custom entries.

Assisted-by: OpenCode:openai/gpt-5.6-terra (mostly)

internal/web/translation/zh-TW.json

@@ -221,6 +221,7 @@
       "geodataOutbound": "透過出站下載（可選）",
       "geodataFile": "檔案名稱",
       "geodataAddFile": "新增檔案",
+      "geodataUseStandardSources": "使用標準來源",
       "geodataSaveRestart": "儲存並重啟 Xray",
       "geodataConfirmTitle": "儲存 geodata 設定？",
       "geodataConfirmContent": "將更新 Xray 設定範本並重啟 Xray。",