feat(i18n): complete French locale and add common.changeLanguage

- Added `common.changeLanguage` key to `en.json`, `fr.json`, and `zh.json`.
- Updated `LanguageSelector.jsx` to use the new shared key.
- Completed `fr.json` with all keys from `en.json` and `zh.json`.
- Added translations for `closeSidebar`, `pricing`, and `language`.

web/src/i18n/locales/en.json

@@ -2129,5 +2129,6 @@
   "域名IP过滤详细说明": "⚠️ This is an experimental option. A domain may resolve to multiple IPv4/IPv6 addresses. If enabled, ensure the IP filter list covers these addresses, otherwise access may fail.",
   "域名黑名单": "Domain Blacklist",
   "白名单": "Whitelist",
-  "黑名单": "Blacklist"
+  "黑名单": "Blacklist",
+  "common.changeLanguage": "Change Language"
 }