Fix PHPStan CI: checkout plugin directly into Moodle tree

The scanDirectories relative paths (../../lib, ../../course) need the
plugin to physically live at local/githubsync within the Moodle tree.
Previous approach used symlinks which broke real-path resolution.

Now: checkout Moodle as root, then checkout plugin into local/githubsync.

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

Author: allanhaggett

.github/workflows/phpstan.yml

@@ -12,31 +12,26 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Checkout plugin
-        uses: actions/checkout@v4
-        with:
-          path: local/githubsync
-
       - name: Checkout Moodle
         uses: actions/checkout@v4
         with:
           repository: moodle/moodle
           ref: MOODLE_405_STABLE
-          path: moodle
+
+      - name: Checkout plugin into Moodle
+        uses: actions/checkout@v4
+        with:
+          path: local/githubsync
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
           php-version: '8.2'
           tools: composer:v2
 
-      - name: Link plugin into Moodle
-        run: |
-          ln -s $GITHUB_WORKSPACE/local/githubsync $GITHUB_WORKSPACE/moodle/local/githubsync
-
       - name: Create Moodle config
         run: |
-          cat > $GITHUB_WORKSPACE/moodle/config.php << 'MOODLECFG'
+          cat > config.php << 'MOODLECFG'
           <?php
           $CFG = new stdClass();
           $CFG->dirroot = __DIR__;