Add CI pipeline, Meilisearch service, CacheService and code quality tools

- CI: lint, PHPStan, PHP CS Fixer, ESLint, Stylelint, security audit, build
- MeilisearchService: async via Messenger, sync search
- MeilisearchMessage + handler for async operations
- CacheService with CacheKey enum (TTL per key, remember pattern)
- Meilisearch env vars in .env.local, vault and env.local.j2
- Messenger routing for MeilisearchMessage
- PHPStan level 6, ESLint, Stylelint configs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

symfony.lock

@@ -38,6 +38,18 @@
     "endroid/qr-code-bundle": {
         "version": "6.1.0"
     },
+    "friendsofphp/php-cs-fixer": {
+        "version": "3.94",
+        "recipe": {
+            "repo": "github.com/symfony/recipes",
+            "branch": "main",
+            "version": "3.39",
+            "ref": "97aaf9026490db73b86c23d49e5774bc89d2b232"
+        },
+        "files": [
+            ".php-cs-fixer.dist.php"
+        ]
+    },
     "league/flysystem-bundle": {
         "version": "3.6",
         "recipe": {
@@ -72,6 +84,15 @@
             "config/packages/nelmio_security.yaml"
         ]
     },
+    "phpstan/phpstan": {
+        "version": "2.1",
+        "recipe": {
+            "repo": "github.com/symfony/recipes-contrib",
+            "branch": "main",
+            "version": "1.0",
+            "ref": "5e490cc197fb6bb1ae22e5abbc531ddc633b6767"
+        }
+    },
     "phpunit/phpunit": {
         "version": "13.0",
         "recipe": {