feat(settings): add 'Apply to Claude Code extension' toggle

- Apply immediately on save (write or remove primaryApiKey)
- Honor setting on provider switch (enabled: write for non-official, remove for official; disabled: no auto writes)
- Remove per-provider Claude plugin buttons from ProviderList
- Upsert primaryApiKey=any preserving other fields; respect override dir
- Add zh/en i18n for the new setting

src/types.ts

@@ -41,6 +41,8 @@ export interface Settings {
   showInTray: boolean;
   // 点击关闭按钮时是否最小化到托盘而不是关闭应用
   minimizeToTrayOnClose: boolean;
+  // 启用 Claude 插件联动（写入 ~/.claude/config.json 的 primaryApiKey）
+  enableClaudePluginIntegration?: boolean;
   // 覆盖 Claude Code 配置目录（可选）
   claudeConfigDir?: string;
   // 覆盖 Codex 配置目录（可选）