fix: add symfony/redis-messenger + real healthchecks

worker-async crashed in a loop with 'No transport supports Messenger DSN
redis://...' because symfony/redis-messenger was never installed — 10x restart
killed the whole stack. Add the package (v7.4.8).

Also harden healthchecks:
- app: hit the real /health route via PHP get_headers (verifies app boots and
  serves, not just that port 80 is open)
- workers: confirm the messenger:consume process is alive via busybox ps

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

composer.json

@@ -9,7 +9,7 @@
         "php": ">=8.2",
         "ext-ctype": "*",
         "ext-iconv": "*",
-        "doctrine/doctrine-bundle": "*",
+        "doctrine/doctrine-bundle": ">=2.18.3",
         "doctrine/doctrine-migrations-bundle": "*",
         "doctrine/orm": "^3.6",
         "lexik/jwt-authentication-bundle": "*",
@@ -26,6 +26,7 @@
         "symfony/property-access": "7.4.*",
         "symfony/property-info": "7.4.*",
         "symfony/rate-limiter": "7.4.*",
+        "symfony/redis-messenger": "7.4.*",
         "symfony/runtime": "7.4.*",
         "symfony/scheduler": "7.4.*",
         "symfony/security-bundle": "7.4.*",
@@ -34,10 +35,10 @@
         "symfony/uid": "7.4.*",
         "symfony/ux-react": "^2.36",
         "symfony/validator": "7.4.*",
-        "symfony/webpack-encore-bundle": "^2.4",
+        "symfony/webpack-encore-bundle": "^2.4.1",
         "symfony/yaml": "7.4.*",
         "twig/twig": "*",
-        "zircote/swagger-php": "*"
+        "zircote/swagger-php": ">=6.2"
     },
     "config": {
         "allow-plugins": {
@@ -91,9 +92,9 @@
     },
     "require-dev": {
         "phpstan/phpstan": "^2.2",
-        "phpstan/phpstan-doctrine": "^2.0",
-        "phpstan/phpstan-symfony": "^2.0",
-        "phpunit/phpunit": "^12.5",
+        "phpstan/phpstan-doctrine": "^2.0.27",
+        "phpstan/phpstan-symfony": "^2.0.20",
+        "phpunit/phpunit": "^12.5.30",
         "symfony/browser-kit": "7.4.*",
         "symfony/css-selector": "7.4.*",
         "symfony/debug-bundle": "7.4.*",