feat: implement browser open functionality and related tests

electron/gateway/handlers/chat.ts

@@ -1,4 +1,4 @@
-import { randomUUID } from 'crypto';
+import { randomUUID } from 'node:crypto';
 import { createProvider } from '@electron/providers';
 import type { BaseProvider } from '@electron/providers/BaseProvider';
 import { providerApiService } from '@electron/service/provider-api-service';
@@ -8,6 +8,7 @@ import type { RawMessage } from '@runtime/shared/chat-model';
 import { sessionStore } from '../session-store';
 import type { GatewayEvent, GatewayRpcParams, GatewayRpcReturns } from '../types';
 import { appendTranscriptLine } from '@electron/utils/token-usage-writer';
+import { maybeHandleBrowserOpenMessage } from '../browser-shortcut';
 
 export interface GatewayChatMessage {
   role: 'system' | 'user' | 'assistant' | 'tool';
@@ -131,6 +132,10 @@ export function handleChatSend(
     },
   });
 
+  if (maybeHandleBrowserOpenMessage(sessionKey, runId, userMessage, broadcast)) {
+    return { runId };
+  }
+
   // 2. Resolve provider account
   const accountId = options?.providerAccountId || providerApiService.getDefault().accountId;
   if (!accountId) {