fix: open external links in VS Code runtime

Route shared URL opening through VS Code host instead of webview window APIs
Add a VS Code runtime URL-open API and bridge handler using vscode.env.openExternal
Keep shared URL helper behavior unchanged for desktop and web

packages/vscode/webview/api/bridge.ts

@@ -138,6 +138,10 @@ export async function executeVSCodeCommand(command: string, args?: unknown[]): P
   return sendBridgeMessage<{ result?: unknown }>('vscode:command', { command, args });
 }
 
+export async function openVSCodeExternalUrl(url: string): Promise<void> {
+  await sendBridgeMessage('vscode:openExternalUrl', { url });
+}
+
 type CommandHandler = (payload: unknown) => void;
 const commandHandlers = new Map<string, CommandHandler>();