Feature Request: Docker setup for isolated headful browser sessions

[UmutAlihan]

As requested in PR #319, here are the use cases for adding a containerized browser setup to the repository.

Currently, playwright-cli runs browsers directly on the host OS. I propose adding a docker/ configuration that runs a Playwright browser server equipped with Xvfb and noVNC, allowing the local CLI to connect via remoteEndpoint.

Key Use Cases:

1. Clean Headful Debugging (Primary): Running --headed locally steals focus, pops up windows, and clutters the desktop. This Docker setup allows live visual debugging in a background browser tab (localhost:6080) without disrupting the developer's local workflow.
2. Agent/LLM Sandboxing: Giving AI agents access to playwright-cli directly on a host OS is a security and state-leakage risk. Running the browser in an ephemeral Docker container provides a strict sandbox that protects the host if an agent goes off-script or downloads malicious files.
3. Corporate Proxies (Custom CAs): Corporate MITM proxies often break host-run browsers. Baking custom .crt certificates into an isolated container is significantly easier and less invasive than modifying the host OS certificate trust store.

Proposed Implementation:

PR #319 provides a ready-to-use Dockerfile (extending mcr.microsoft.com/playwright/mcp), a supervisord setup, and a helper script. Including this prevents users from having to figure out and build this complex Xvfb/noVNC stack from scratch.