Add Playwright/Chromium and Azure CLI to the devcontainer

[Copilot]

Adds browser-automation tooling (Playwright + Chromium) and the Azure CLI to the devcontainer so the environment is ready to use out of the box.

Changes

• Playwright + Chromium (Dockerfile): No devcontainer feature exists for Playwright, so it's installed via the Dockerfile. Installs playwright globally, then playwright install --with-deps chromium to pull Chromium plus its required OS dependencies.

  • Browsers are placed in a shared PLAYWRIGHT_BROWSERS_PATH=/ms-playwright and made world-readable so both the node and root users can run them without re-downloading.

  ENV PLAYWRIGHT_BROWSERS_PATH=/ms-playwright
  RUN npm install -g playwright \
      && playwright install --with-deps chromium \
      && chmod -R a+rx /ms-playwright

• Azure CLI (feature): Added ghcr.io/devcontainers/features/azure-cli:1 pinned to version: latest, per request. Lock file regenerated for the new feature; this also corrected a pre-existing malformed copilot-cli: key.

• README: Documented the Azure CLI feature and Playwright/Chromium under the relevant sections.

Notes

• Pinning az to latest is intentional but makes builds non-reproducible; swap for a specific version if reproducibility is preferred.