feat(http): change default API host to 0.0.0.0 for external access

- 修改 httpApiHost 默认值从 127.0.0.1 到 0.0.0.0
- 允许 HTTP API 服务接受外网访问
- 用户需要配置 httpApiToken 以确保安全

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

electron/services/config.ts

@@ -126,7 +126,7 @@ export class ConfigService {
       httpApiToken: '',
       httpApiEnabled: false,
       httpApiPort: 5031,
-      httpApiHost: '127.0.0.1',
+      httpApiHost: '0.0.0.0',
       messagePushEnabled: false,
       windowCloseBehavior: 'ask',
       quoteLayout: 'quote-top',