Add Playwright end-to-end testing infrastructure to dev container

[sei-npacheco]

Summary

• Configure the dev container to install Playwright (Chromium browser, system dependencies, npm packages)
  and the VS Code Playwright extension automatically during container creation
• Add the crucible-tests repo to repos.json so it is cloned alongside other Crucible repositories
• Register the playwright-test MCP server alongside the existing playwright MCP server so Claude Code can
  plan, generate, and heal tests using Playwright test agents

Changes

• Dockerfile — Add Chromium headless system dependencies (libs, fonts)
• devcontainer.json — Add desktop-lite feature (noVNC on port 6080), ms-playwright.playwright extension,
  Playwright VS Code settings pointing to the test config, forward port 6080, simplify existing feature
  declarations
• postcreate.sh — Run npm install, playwright install chromium, and playwright init-agents for the
  crucible-tests project during container creation
• .gitignore — Ignore generated agent definitions (.claude/agents/)
• .mcp.json — Add playwright-test MCP server entry
• CLAUDE.md — Point Claude Code to the crucible-tests directory for Playwright work
• README.md — Add "Playwright Testing" section covering the VS Code extension, test agents, and CLI usage
• repos.json — Add crucible-tests repository to the libraries clone list

[sei-jbooz]

👍 Looks good to me