build: migrate from npm to pnpm with workspace catalogs

- Switch package manager to pnpm 10 via corepack
- Add pnpm-workspace.yaml with 54+ shared dependency catalogs
- Convert all workspace packages to catalog: and workspace:* protocols
- Upgrade Turborepo from 1.x to 2.8.12 (pipeline -> tasks)
- Upgrade apps/openpage-api from Next 15 to Next 16
- Update Docker, CI workflows, and GitHub Actions for pnpm
- Convert patch file to pnpm native format
- Replace deprecated next lint with standalone eslint
- Update all documentation references from npm to pnpm
- Fix stale dependabot config and documentation paths

.github/actions/playwright-install/action.yml

@@ -10,10 +10,10 @@ runs:
         path: |
           ~/.cache/ms-playwright
           ${{ github.workspace }}/node_modules/playwright
-        key: playwright-${{ hashFiles('**/package-lock.json') }}
+        key: playwright-${{ hashFiles('**/pnpm-lock.yaml') }}
         restore-keys: playwright-
 
     - name: Install playwright
       if: steps.cache-playwright.outputs.cache-hit != 'true'
-      run: npx playwright install --with-deps
+      run: pnpm exec playwright install --with-deps
       shell: bash