feat: add Universal Provider feature (#348)

* feat: add Universal Provider feature

- Add Universal Provider data structures and type definitions
- Implement backend CRUD operations and sync functionality
- Add frontend UI components (UniversalProviderPanel, Card, FormModal)
- Add NewAPI icon and preset configuration
- Support cross-app (Claude/Codex/Gemini) configuration sync
- Add website URL field for providers
- Implement real-time refresh via event notifications
- Add i18n support (Chinese/English/Japanese)

* feat: integrate universal provider presets into add provider dialog

- Add universal provider presets (NewAPI, Custom Gateway) to preset selector
- Show universal presets with Layers icon badge in preset selector
- Open UniversalProviderFormModal when universal preset is clicked
- Pass initialPreset to auto-fill form when opened from add dialog
- Add i18n keys for addSuccess/addFailed messages
- Keep separate universal provider panel for management

* refactor: move universal provider management to add dialog

- Remove Layers button from main navigation header
- Add 'Manage' button next to universal provider presets
- Open UniversalProviderPanel from within add provider dialog
- Add i18n keys for 'manage' in all locales

* style: display universal provider presets on separate line

- Move universal provider section to a new row with border separator
- Add label '统一供应商:' to clarify the section

* style: unify universal provider label style with preset label

- Use FormLabel component for consistent styling
- Add background to 'Manage' button matching preset buttons
- Update icon size and button padding for consistency

* feat: add sync functionality and JSON preview for Universal Provider

* fix: add missing in_failover_queue field to Provider structs

After rebasing to main, the Provider struct gained a new
`in_failover_queue` field. This fix adds the missing field
to the three to_*_provider() methods in UniversalProvider.

* refactor: redesign AddProviderDialog with tab-based layout

- Add tabs to separate app-specific providers and universal providers
- Move "Add Universal Provider" button from panel header to footer
- Remove unused handleAdd callback and clean up imports
- Update emptyHint i18n text to reference the footer button

* fix: append /v1 suffix to Codex base_url in Universal Provider

Codex uses OpenAI-compatible API which requires the /v1 endpoint suffix.
The Universal Provider now automatically appends /v1 to base_url when
generating Codex provider config if not already present.

- Handle trailing slashes to avoid double slashes
- Apply fix to both backend (to_codex_provider) and frontend preview

* feat: auto-sync universal provider to apps on creation

Previously, users had to manually click sync after adding a universal
provider. Now it automatically syncs to Claude/Codex/Gemini on creation,
providing a smoother user experience.

---------

Co-authored-by: Jason <farion1231@gmail.com>

src/i18n/locales/en.json

@@ -66,6 +66,8 @@
     "exitEditMode": "Exit Edit Mode"
   },
   "provider": {
+    "tabProvider": "Provider",
+    "tabUniversal": "Universal",
     "noProviders": "No providers added yet",
     "noProvidersDescription": "Click the \"Add Provider\" button in the top right to configure your first API provider",
     "currentlyUsing": "Currently Using",
@@ -1135,5 +1137,49 @@
     "streamingFirstByte": "Streaming First Byte Timeout",
     "streamingIdle": "Streaming Idle Timeout",
     "nonStreaming": "Non-Streaming Timeout"
+  },
+  "universalProvider": {
+    "title": "Universal Provider",
+    "description": "Universal providers manage Claude, Codex, and Gemini configurations simultaneously. Changes are automatically synced to all enabled apps.",
+    "add": "Add Universal Provider",
+    "edit": "Edit Universal Provider",
+    "empty": "No universal providers yet",
+    "emptyHint": "Click the \"Add Universal Provider\" button below to create one",
+    "selectPreset": "Select Preset Type",
+    "name": "Name",
+    "namePlaceholder": "e.g., My NewAPI",
+    "baseUrl": "API URL",
+    "apiKey": "API Key",
+    "websiteUrl": "Website URL",
+    "websiteUrlPlaceholder": "https://example.com (optional, displayed in the list)",
+    "notes": "Notes",
+    "notesPlaceholder": "Optional: Add notes",
+    "enabledApps": "Enabled Apps",
+    "modelConfig": "Model Configuration",
+    "model": "Model",
+    "sync": "Sync to Apps",
+    "synced": "Synced to all apps",
+    "syncError": "Sync failed",
+    "noAppsEnabled": "No apps enabled",
+    "added": "Universal provider added",
+    "addedAndSynced": "Universal provider added and synced",
+    "updated": "Universal provider updated",
+    "deleted": "Universal provider deleted",
+    "addSuccess": "Universal provider added successfully",
+    "addFailed": "Failed to add universal provider",
+    "manage": "Manage",
+    "loadError": "Failed to load universal providers",
+    "saveError": "Failed to save universal provider",
+    "deleteError": "Failed to delete universal provider",
+    "deleteConfirmTitle": "Delete Universal Provider",
+    "deleteConfirmDescription": "Are you sure you want to delete \"{{name}}\"? This will also delete its generated provider configurations in each app.",
+    "syncConfirmTitle": "Sync Universal Provider",
+    "syncConfirmDescription": "Syncing \"{{name}}\" will overwrite the associated provider configurations in Claude, Codex, and Gemini. Do you want to continue?",
+    "syncConfirm": "Sync",
+    "saveAndSync": "Save & Sync",
+    "savedAndSynced": "Saved and synced to all apps",
+    "saveAndSyncError": "Failed to save and sync",
+    "configJsonPreview": "Config JSON Preview",
+    "configJsonPreviewHint": "The following configurations will be synced to each app (only the displayed fields will be overwritten, other custom settings will be preserved)"
   }
 }

src/i18n/locales/ja.json

@@ -66,6 +66,8 @@
     "exitEditMode": "編集モードを終了"
   },
   "provider": {
+    "tabProvider": "プロバイダー",
+    "tabUniversal": "統一プロバイダー",
     "noProviders": "まだプロバイダーがありません",
     "noProvidersDescription": "右上の「プロバイダーを追加」を押して最初の API プロバイダーを登録してください",
     "currentlyUsing": "現在使用中",
@@ -1135,5 +1137,48 @@
     "streamingFirstByte": "ストリーミング初回バイトタイムアウト",
     "streamingIdle": "ストリーミングアイドルタイムアウト",
     "nonStreaming": "非ストリーミングタイムアウト"
+  },
+  "universalProvider": {
+    "title": "統合プロバイダー",
+    "description": "統合プロバイダーは Claude、Codex、Gemini の設定を同時に管理します。変更は有効なすべてのアプリに自動的に同期されます。",
+    "add": "統合プロバイダーを追加",
+    "edit": "統合プロバイダーを編集",
+    "empty": "統合プロバイダーがありません",
+    "emptyHint": "下の「統合プロバイダーを追加」ボタンをクリックして作成してください",
+    "selectPreset": "プリセットタイプを選択",
+    "name": "名前",
+    "namePlaceholder": "例：私の NewAPI",
+    "baseUrl": "API URL",
+    "apiKey": "API キー",
+    "websiteUrl": "ウェブサイト URL",
+    "websiteUrlPlaceholder": "https://example.com（オプション、リストに表示されます）",
+    "notes": "メモ",
+    "notesPlaceholder": "オプション：メモを追加",
+    "enabledApps": "有効なアプリ",
+    "modelConfig": "モデル設定",
+    "model": "モデル",
+    "sync": "アプリに同期",
+    "synced": "すべてのアプリに同期しました",
+    "syncError": "同期に失敗しました",
+    "noAppsEnabled": "有効なアプリがありません",
+    "added": "統合プロバイダーを追加しました",
+    "updated": "統合プロバイダーを更新しました",
+    "deleted": "統合プロバイダーを削除しました",
+    "addSuccess": "統合プロバイダーを追加しました",
+    "addFailed": "統合プロバイダーの追加に失敗しました",
+    "manage": "管理",
+    "loadError": "統合プロバイダーの読み込みに失敗しました",
+    "saveError": "統合プロバイダーの保存に失敗しました",
+    "deleteError": "統合プロバイダーの削除に失敗しました",
+    "deleteConfirmTitle": "統合プロバイダーを削除",
+    "deleteConfirmDescription": "「{{name}}」を削除してもよろしいですか？各アプリで生成されたプロバイダー設定も削除されます。",
+    "syncConfirmTitle": "統合プロバイダーを同期",
+    "syncConfirmDescription": "「{{name}}」を同期すると、Claude、Codex、Gemini の関連プロバイダー設定が上書きされます。続行しますか？",
+    "syncConfirm": "同期",
+    "saveAndSync": "保存して同期",
+    "savedAndSynced": "すべてのアプリに保存・同期されました",
+    "saveAndSyncError": "保存と同期に失敗しました",
+    "configJsonPreview": "設定 JSON プレビュー",
+    "configJsonPreviewHint": "以下は各アプリに同期される設定内容です（表示されているフィールドのみ上書きされ、他のカスタム設定は保持されます）"
   }
 }

src/i18n/locales/zh.json

@@ -66,6 +66,8 @@
     "exitEditMode": "退出编辑模式"
   },
   "provider": {
+    "tabProvider": "供应商",
+    "tabUniversal": "统一供应商",
     "noProviders": "还没有添加任何供应商",
     "noProvidersDescription": "点击右上角的\"添加供应商\"按钮开始配置您的第一个API供应商",
     "currentlyUsing": "当前使用",
@@ -1135,5 +1137,49 @@
     "streamingFirstByte": "流式首字节超时",
     "streamingIdle": "流式静默超时",
     "nonStreaming": "非流式超时"
+  },
+  "universalProvider": {
+    "title": "统一供应商",
+    "description": "统一供应商可以同时管理 Claude、Codex 和 Gemini 的配置。修改后会自动同步到所有启用的应用。",
+    "add": "添加统一供应商",
+    "edit": "编辑统一供应商",
+    "empty": "还没有统一供应商",
+    "emptyHint": "点击下方「添加统一供应商」按钮创建一个",
+    "selectPreset": "选择预设类型",
+    "name": "名称",
+    "namePlaceholder": "例如：我的 NewAPI",
+    "baseUrl": "API 地址",
+    "apiKey": "API Key",
+    "websiteUrl": "官网地址",
+    "websiteUrlPlaceholder": "https://example.com（可选，用于在列表中显示）",
+    "notes": "备注",
+    "notesPlaceholder": "可选：添加备注信息",
+    "enabledApps": "启用的应用",
+    "modelConfig": "模型配置",
+    "model": "模型",
+    "sync": "同步到应用",
+    "synced": "已同步到所有应用",
+    "syncError": "同步失败",
+    "noAppsEnabled": "未启用任何应用",
+    "added": "统一供应商已添加",
+    "addedAndSynced": "统一供应商已添加并同步",
+    "updated": "统一供应商已更新",
+    "deleted": "统一供应商已删除",
+    "addSuccess": "统一供应商添加成功",
+    "addFailed": "统一供应商添加失败",
+    "manage": "管理",
+    "loadError": "加载统一供应商失败",
+    "saveError": "保存统一供应商失败",
+    "deleteError": "删除统一供应商失败",
+    "deleteConfirmTitle": "删除统一供应商",
+    "deleteConfirmDescription": "确定要删除 \"{{name}}\" 吗？这将同时删除它在各应用中生成的供应商配置。",
+    "syncConfirmTitle": "同步统一供应商",
+    "syncConfirmDescription": "同步 \"{{name}}\" 将会覆盖 Claude、Codex 和 Gemini 中关联的供应商配置。确定要继续吗？",
+    "syncConfirm": "同步",
+    "saveAndSync": "保存并同步",
+    "savedAndSynced": "已保存并同步到所有应用",
+    "saveAndSyncError": "保存并同步失败",
+    "configJsonPreview": "配置 JSON 预览",
+    "configJsonPreviewHint": "以下是将要同步到各应用的配置内容（仅覆盖显示的字段，保留其他自定义配置）"
   }
 }