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

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

lib/i18n/dictionaries/zh.json

@@ -14,6 +14,7 @@
         "about": "关于",
         "editor": "编辑器",
         "newChat": "开始新对话",
+        "github": "GitHub",
         "settings": "设置",
         "hidePanel": "隐藏聊天面板 (Ctrl+B)",
         "showPanel": "显示聊天面板 (Ctrl+B)",
@@ -87,6 +88,8 @@
         "overrides": "覆盖",
         "clearSettings": "清除设置",
         "useServerDefault": "使用服务器默认值",
+        "language": "语言",
+        "languageDescription": "选择界面语言。",
         "theme": "主题",
         "themeDescription": "界面和 DrawIO 画布的深色/浅色模式。",
         "drawioStyle": "DrawIO 样式",