move Language Selector into SettingDialog (#352)

* fix:custom model setting bug

* refactor: consolidate aiProvider checks for cleaner code

* fix:Integrated the language selection option into the `SettingsDialog`

* fix:useSearchParams() should be wrapped in a suspense boundary at page

* fix: improve semantic HTML and maintainability

- Replace nested button>a with proper anchor element for GitHub link
- Use i18n.locales.map() with LANGUAGE_LABELS for language options

---------

Co-authored-by: dayuan.jiang <jdy.toh@gmail.com>

lib/i18n/dictionaries/en.json

@@ -14,6 +14,7 @@
         "about": "About",
         "editor": "Editor",
         "newChat": "Start fresh chat",
+        "github": "GitHub",
         "settings": "Settings",
         "hidePanel": "Hide chat panel (Ctrl+B)",
         "showPanel": "Show chat panel (Ctrl+B)",
@@ -87,6 +88,8 @@
         "overrides": "Overrides",
         "clearSettings": "Clear Settings",
         "useServerDefault": "Use Server Default",
+        "language": "Language",
+        "languageDescription": "Choose your interface language.",
         "theme": "Theme",
         "themeDescription": "Dark/Light mode for interface and DrawIO canvas.",
         "drawioStyle": "DrawIO Style",