ci: drop saschaegerer/phpstan-typo3, not compatible with TYPO3 12.4 + phpstan ^2

No version of saschaegerer/phpstan-typo3 bridges phpstan ^2 and TYPO3 ^12.4.
PHPStan resolves TYPO3 types directly from the installed typo3/cms-core source.
Remove phpstan-ci.neon wrapper which existed solely to include the extension.

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

Author: fpodschwadek

.github/workflows/phpstan.yml

@@ -22,4 +22,4 @@ jobs:
         run: composer install --no-interaction --prefer-dist
 
       - name: Run PHPStan
-        run: vendor/bin/phpstan analyse -c phpstan-ci.neon --no-progress
+        run: vendor/bin/phpstan analyse -c phpstan.neon --no-progress

composer.json

@@ -30,7 +30,6 @@
     "codeception/module-db": "^3.2",
     "codeception/verify": "^3.2",
     "phpstan/phpstan": "^2",
-    "saschaegerer/phpstan-typo3": "^2",
     "ssch/typo3-rector": "^3.8",
     "typo3/coding-standards": "^0.8.0",
     "a9f/typo3-fractor": "^0.5.0"