feat: migration PHPStan niveau 8 - workflows et corrections compiler

- Mise à jour tous les workflows quality.yaml et phpstan-*.yaml vers level: 8
- Corrections PHPStan compiler: SFTP/FTP Server, Api/HttpHook Runtime (ClosureUse)
- Plugin Filtering Drop/Reject: refactor buildExclusions avec array_slice
- Deferred::resolve(null), asStmt() pour builder->getNode()
- Plugin FTP Loader: returnType Identifier au lieu de ConstFetch
- Ignores phpstan.neon pour Cloud API types

Made-with: Cursor

Author: gplanchat

composer.json

@@ -20,7 +20,7 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": "^8.0",
+        "php": "^8.4",
         "psr/simple-cache": "^3.0",
         "psr/log": "^1.0",
         "php-etl/pipeline-contracts": "^0.3.3",