[Bug]: --extension mode: relay does not reconnect to browser extension after disconnect #41874

Environment

• @playwright/mcp v0.0.29 (current latest)
• Chrome extension: "Playwright MCP Bridge" (mmlmfjhmonkocbjadbfplnigmagldckm)
• Chrome (stable) on macOS
• Client: Claude Code MCP client

Summary

When the browser extension disconnects from the MCP relay (e.g. Chrome service worker idle timeout after 5 min of inactivity, browser restart, or extension reload), the relay never attempts to reconnect. Any subsequent MCP tool call fails with Extension not connected, and the only recovery is restarting the entire MCP server.

Steps to reproduce

1. Start the MCP server with extension mode: PLAYWRIGHT_MCP_EXTENSION_TOKEN=<token> npx @playwright/mcp --extension --browser chrome
2. Connect the extension and use it normally.
3. Wait ~5 minutes without any tool calls (Chrome MV3 service worker idle timeout), or close and reopen the browser, or reload the extension.
4. Call any MCP tool (e.g. browser_navigate).

Expected: the relay automatically re-opens connect.html and reconnects (token bypass makes this silent).

Actual: tool call fails with Extension not connected. The relay WebSocket server is still running but _extensionConnection is null and nothing re-triggers _connectBrowser.

Root cause

In packages/playwright-core/src/tools/mcp/cdpRelay.ts, when the extension connection closes, the handler clears CDP state and calls onExtensionDisconnect but never re-invokes _openConnectPageInBrowser to bring the extension back.

establishExtensionConnection is only called once from extensionContextFactory.ts at startup and is never called again, so there is no automatic recovery path.

Suggested fix

After extension connection close resets state, call _openConnectPageInBrowser again. Guard it so it does not fire during initial construction or intentional stop() shutdown.