ci: fix lint stage — use PHP 8.2 for dev tooling

Composer dev deps (phpunit, php-scoper) require PHP 8.1+. PHP 8.0
compatibility is already covered by the integration matrix.

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

Author: Jordanburch101

.github/workflows/ci.yml

@@ -12,21 +12,17 @@ concurrency:
 jobs:
   # ── Stage 1: Fast checks (~30s) ──────────────────────────────────────
   lint:
-    name: Lint (PHP ${{ matrix.php-version }})
+    name: Lint
     runs-on: ubuntu-latest
 
-    strategy:
-      matrix:
-        php-version: ['8.0', '8.2']
-
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
 
-      - name: Setup PHP ${{ matrix.php-version }}
+      - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: ${{ matrix.php-version }}
+          php-version: '8.2'
           tools: cs2pr
           coverage: none