Add Chrome channel persistent context launch

- Enable launchPersistentContext when BROWSE_CHANNEL is set
- Support macOS SSO by using temporary profile directory
- Maintain headless and sandbox handling for other browsers

browse/src/browser-manager.ts

@@ -287,6 +287,7 @@ export class BrowserManager {
     // BROWSE_EXTENSIONS_DIR points to an unpacked Chrome extension directory.
     // Extensions only work in headed mode, so we use an off-screen window.
     const extensionsDir = process.env.BROWSE_EXTENSIONS_DIR;
+    const channel = process.env.BROWSE_CHANNEL;
     const { STEALTH_LAUNCH_ARGS } = await import('./stealth');
     const launchArgs: string[] = [...STEALTH_LAUNCH_ARGS];
     let useHeadless = true;
@@ -310,7 +311,7 @@ export class BrowserManager {
       console.log(`[browse] Extensions loaded from: ${extensionsDir}`);
     }
 
-    this.browser = await chromium.launch({
+    const launchOpts = {
       headless: useHeadless,
       // On Windows, Chromium's sandbox fails when the server is spawned through
       // the Bun→Node process chain (GitHub #276). Disable it — local daemon
@@ -320,7 +321,24 @@ export class BrowserManager {
       chromiumSandbox: shouldEnableChromiumSandbox(),
       ...(launchArgs.length > 0 ? { args: launchArgs } : {}),
       ...(this.proxyConfig ? { proxy: this.proxyConfig } : {}),
+    };
+
+    const contextOpts: BrowserContextOptions = {
+      viewport: this.currentViewport,
+      deviceScaleFactor: this.deviceScaleFactor,
+      ...(this.customUserAgent ? { userAgent: this.customUserAgent } : {}),
+    };
+
+    if (channel) {
+      // launchPersistentContext enables macOS platform SSO (newContext does not)
+      this.context = await chromium.launchPersistentContext('', {
+        ...launchOpts, ...contextOpts, channel,
       });
+      this.browser = this.context.browser();
+    } else {
+      this.browser = await chromium.launch(launchOpts);
+      this.context = await this.browser.newContext(contextOpts);
+    }
 
     // Chromium disconnect → distinguish clean user-quit from crash. Both
     // events look identical to Playwright (one 'disconnected' fires), but
@@ -335,15 +353,6 @@ export class BrowserManager {
       void handleChromiumDisconnect(this.browser);
     });
 
-    const contextOptions: BrowserContextOptions = {
-      viewport: { width: this.currentViewport.width, height: this.currentViewport.height },
-      deviceScaleFactor: this.deviceScaleFactor,
-    };
-    if (this.customUserAgent) {
-      contextOptions.userAgent = this.customUserAgent;
-    }
-    this.context = await this.browser.newContext(contextOptions);
-
     if (Object.keys(this.extraHeaders).length > 0) {
       await this.context.setExtraHTTPHeaders(this.extraHeaders);
     }