fix(ci): build before test and install Playwright browsers in pages workflow

The `Updating Github pages` workflow has been failing on every push
to main since the Karma→Playwright migration (commit be7e235). Two
issues, both fixed here:

1. **Build runs AFTER test, but the integration test requires the
   build output.** `tests/integration/full-chain.spec.ts:5` does
   `require('../../lib/index')` at module load time. `lib/` is the
   rollup output produced by `yarn build`. The current step order
   in `Generating coverage and docs` was `yarn test` then `yarn
   build`, so Playwright's test-file discovery crashed with
   `Error: Cannot find module '../../lib/index'` before any browser
   even launched.

2. **Playwright's bundled chromium was never installed.** The
   workflow installs system `google-chrome-stable` (a Karma-era
   leftover), but Playwright uses its own bundled chromium binary,
   not the system Chrome. Without `playwright install`, the
   browser tests would have failed at browser-launch time even
   after fixing (1).

`qa.yml` already had both pieces in place — that's why PR-time
checks have been passing while `pages.yml` has been red on every
merge. This change brings `pages.yml` into alignment.

The system Chrome install block is left untouched here — removing
it is scope-creep cleanup that should be a separate PR.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: abbaseya

.github/workflows/pages.yml

@@ -35,11 +35,16 @@ jobs:
       - name: Installing npm packages
         run: yarn install --immutable
 
+      - name: Install Playwright browsers
+        run: |
+          cd packages/js-sdk
+          yarn playwright install --with-deps chromium
+
       - name: Generating coverage and docs
         run: |
           cd packages/js-sdk
-          yarn test
           yarn build
+          yarn test
 
       - name: Checkout gh-pages
         uses: actions/checkout@v3