revert(ci): restore setup-php workflow from 7d9278f

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.forgejo/workflows/ci.yml

@@ -10,8 +10,6 @@ jobs:
   test:
     name: PHP ${{ matrix.php }}
     runs-on: ubuntu-latest
-    container:
-      image: lthn/build:php-${{ matrix.php }}
 
     strategy:
       fail-fast: true
@@ -21,6 +19,13 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Setup PHP
+        uses: https://github.com/shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          extensions: dom, curl, libxml, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite
+          coverage: pcov
+
       - name: Install dependencies
         run: composer install --prefer-dist --no-interaction --no-progress