ci: configure Playwright browser caching

Add Playwright browser installation to GitHub Actions:
- Cache browsers at ~/.cache/ms-playwright (~100MB)
- Install browsers and deps on cache miss
- Only install system deps on cache hit
- Set PLAYWRIGHT_HEADLESS=true for CI runs

Author: mroderick

.github/workflows/ruby.yml

@@ -40,6 +40,21 @@ jobs:
         # .ruby-version provides the Ruby version implicitly.
         bundler-cache: true
 
+    - name: Cache Playwright browsers
+      uses: actions/cache@v3
+      id: playwright-cache
+      with:
+        path: ~/.cache/ms-playwright
+        key: playwright-${{ runner.os }}-1.58.0
+
+    - name: Install Playwright browsers (cache miss)
+      if: steps.playwright-cache.outputs.cache-hit != 'true'
+      run: npx --yes playwright@1.58.0 install --with-deps chromium
+
+    - name: Install Playwright system deps (cache hit)
+      if: steps.playwright-cache.outputs.cache-hit == 'true'
+      run: npx --yes playwright@1.58.0 install-deps chromium
+
     - name: Setup test databases
       env:
         DATABASE_URL: postgres://postgres:postgres@localhost:5432
@@ -50,6 +65,8 @@ jobs:
       env:
         DATABASE_URL: postgres://postgres:postgres@localhost:5432
         CI_NODE_INDEX: ${{ matrix.ci_node_index }}
+        RAILS_ENV: test
+        PLAYWRIGHT_HEADLESS: true    
       run: |
         bundle exec parallel_rspec spec/ \
           -n ${{ matrix.ci_node_total }} \