fix(ci): run pnpm install in setup action to restore bin links

The cached node_modules restored by the setup action lacks proper pnpm
bin linking, causing `pnpm exec playwright` to fail with "Command not found".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: logaretm

.github/actions/setup/action.yml

@@ -16,3 +16,6 @@ runs:
           packages/*/node_modules
           packages/*/dist
         key: build-${{ github.sha }}
+    - name: Install dependencies
+      run: pnpm install
+      shell: bash