feat: add GitHub CI runner for allowlisted Playwright tests

## Summary Adds a new GitHub CI job to run Playwright E2E tests with an allowlist mechanism for selective test execution. ## Changes - **New CI Job**: `playwright-tests` runs in parallel with existing CI jobs - **Browser Setup**: Installs Chromium and WebKit with system dependencies - **Allowlist System**: `.playwright-ci-allowlist` file controls which tests run in CI - **Artifact Upload**: Test results and reports uploaded for debugging - **Pipeline Integration**: Build-and-package now waits for Playwright tests ## Currently Enabled Tests - `e2e/console-forward.e2e.ts` - Console forwarding functionality ## Allowlist Format ``` # Add one test file path per line # Comments start with # e2e/console-forward.e2e.ts ``` ## CI Behavior - Reads allowlist file, ignoring comments and empty lines - Runs `npm run test:playwright -- <test-files>` - Skips gracefully if allowlist is empty - Uploads results even on test failures ## Benefits - **Selective Testing**: Only run stable/important tests in CI - **Easy Management**: Add tests by editing allowlist file - **Artifact Storage**: Test results preserved for 7 days - **Parallel Execution**: Doesn't slow down other CI jobs 🤖 Generated with [Claude Code](https://claude.ai/code)