[Experimental] Ship a self-contained Playwright runtime under js/

Problem/Motivation

The runtime browser tools in this module rely on Playwright being installed separately (a global/system install, or a manual step outside the module). There is currently no self-contained way to ship and provision Playwright with the module itself, which makes the runtime browser capture tools harder to use out of the box.

Proposed resolution

Add a js/ folder that owns a minimal package.json with a single playwright runtime dependency, kept separate from the root webship-js BDD test suite. The module's PlaywrightRunner now:

• Prefers resolving the capture script from js/<name>, falling back to scripts/<name> for back-compatibility.
• On first use, provisions Playwright and headless Chromium into a writable browsers directory (PLAYWRIGHT_BROWSERS_PATH) when the bundled js/ layout is present but not yet installed, so the tools work without a separate manual install step.
• Runs capture() with PLAYWRIGHT_BROWSERS_PATH pointed at that provisioned directory.

The node_modules package contents and downloaded browsers are not committed to the repository (a js/.gitignore excludes them - too large for a module repo). Provisioning is best-effort and degrades gracefully if it cannot complete in a given environment.

This is marked EXPERIMENTAL: a test MR that may or may not work in every environment.

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Update Release Notes
• ❌ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• N/A