feat(providers): add notes field for provider management

- Add notes field to Provider model (backend and frontend)
- Display notes with higher priority than URL in provider card
- Style notes as non-clickable text to differentiate from URLs
- Add notes input field in provider form
- Add i18n support (zh/en) for notes field

src/types.ts

@@ -14,6 +14,8 @@ export interface Provider {
   category?: ProviderCategory;
   createdAt?: number; // 添加时间戳（毫秒）
   sortIndex?: number; // 排序索引（用于自定义拖拽排序）
+  // 备注信息
+  notes?: string;
   // 新增：是否为商业合作伙伴
   isPartner?: boolean;
   // 可选：供应商元数据（仅存于 ~/.cc-switch/config.json，不写入 live 配置）