Add built-in proxy settings for Electron and Gateway (#239)

Co-authored-by: zuolingxuan <zuolingxuan@bytedance.com>

electron/main/proxy.ts

@@ -0,0 +1,22 @@
+import { session } from 'electron';
+import { getAllSettings, type AppSettings } from '../utils/store';
+import { buildElectronProxyConfig } from '../utils/proxy';
+import { logger } from '../utils/logger';
+
+export async function applyProxySettings(
+  partialSettings?: Pick<AppSettings, 'proxyEnabled' | 'proxyServer' | 'proxyBypassRules'>
+): Promise<void> {
+  const settings = partialSettings ?? await getAllSettings();
+  const config = buildElectronProxyConfig(settings);
+
+  await session.defaultSession.setProxy(config);
+  try {
+    await session.defaultSession.closeAllConnections();
+  } catch (error) {
+    logger.debug('Failed to close existing connections after proxy update:', error);
+  }
+
+  logger.info(
+    `Applied Electron proxy (${config.mode}${config.proxyRules ? `, server=${config.proxyRules}` : ''}${config.proxyBypassRules ? `, bypass=${config.proxyBypassRules}` : ''})`
+  );
+}