Fix Keycloak service entrypoint configuration

- Use Keycloak's default entrypoint /opt/keycloak/bin/kc.sh
- Pass start-dev as command argument (not via shell wrapper)
- Keep KC_DB=dev-file for in-memory H2 database
- This should avoid Docker flag parsing issues with -c flag

Author: felixevers

.github/workflows/tests.yml

@@ -91,9 +91,8 @@ jobs:
           --health-timeout 10s
           --health-retries 30
           --health-start-period 40s
-          --entrypoint /bin/sh
-          -c
-          "/opt/keycloak/bin/kc.sh start-dev"
+          --entrypoint /opt/keycloak/bin/kc.sh
+          start-dev
         ports:
           - 8080:8080