ci: replace sleep with compose --wait + nginx healthcheck

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: chr-hertel

.github/workflows/pipeline.yaml

@@ -91,8 +91,7 @@ jobs:
         run: |
           mkdir -p tests/Conformance/sessions tests/Conformance/logs
           chmod -R 777 tests/Conformance/sessions tests/Conformance/logs
-          docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d
-          sleep 5
+          docker compose -f tests/Conformance/Fixtures/docker-compose.yml up -d --wait
 
       - name: Run conformance tests
         working-directory: ./tests/Conformance

tests/Conformance/Fixtures/docker-compose.yml

@@ -10,6 +10,12 @@ services:
       - php-fpm
     networks:
       - mcp-net
+    healthcheck:
+      test: ["CMD", "wget", "-q", "-O-", "http://localhost/"]
+      interval: 2s
+      timeout: 2s
+      retries: 10
+      start_period: 2s
 
   php-fpm:
     image: php:8.4-fpm-alpine