Fix CI: revert ui-test to Playwright container approach

Using ubuntu-latest with --with-deps downloads hundreds of system
packages. Revert to using the Playwright container which has all
browser dependencies pre-installed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: eakmanrq <6326532+eakmanrq@users.noreply.github.com>

Author: eakmanrq

.github/workflows/pr.yaml

@@ -219,26 +219,18 @@ jobs:
       needs.changes.outputs.client == 'true' || needs.changes.outputs.ci ==
       'true' || github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
+    container:
+      image: mcr.microsoft.com/playwright:v1.54.1-jammy
     steps:
       - uses: actions/checkout@v5
-      - uses: actions/setup-node@v6
-        with:
-          node-version: '20'
-      - uses: pnpm/action-setup@v4
-        with:
-          version: latest
-      - name: Get pnpm store directory
-        id: pnpm-cache
-        run: echo "store=$(pnpm store path)" >> $GITHUB_OUTPUT
-      - uses: actions/cache@v4
-        with:
-          path: ${{ steps.pnpm-cache.outputs.store }}
-          key: pnpm-store-${{ hashFiles('pnpm-lock.yaml') }}
-          restore-keys: pnpm-store-
+      - name: Install pnpm via corepack
+        run: |
+          npm install --global corepack@latest
+          corepack enable
+          corepack prepare pnpm@latest-10 --activate
+          pnpm config set store-dir .pnpm-store
       - name: Install dependencies
         run: pnpm install
-      - name: Install Playwright browsers
-        run: pnpm --prefix web/client exec playwright install --with-deps
       - name: Run tests
         run: npm --prefix web/client run test