refactor: update docker images to use custom registry and optimize configurations

Switched container images in `dc-infra.yaml` to a custom Docker registry for better control and consistency across deployments. Added Keycloak with enhanced configurations and updated several container restart policies, memory allocations, and healthcheck settings for improved performance and compatibility.

dc-backend.yaml

@@ -43,11 +43,11 @@ services:
       SPRING_DATASOURCE_USERNAME: "${POSTGRES_USER:-pg-user}"
       SPRING_DATASOURCE_PASSWORD: "${POSTGRES_PASSWORD:-pg-password}"
 
-      # --- REDIS ---
-      SPRING_DATA_REDIS_HOST: "${REDIS_SERVER_HOSTNAME:-redis}"
-      SPRING_DATA_REDIS_PORT: "${REDIS_SERVICE_PORT:-6379}"
-      SPRING_DATA_REDIS_PASSWORD: "${REDIS_PASSWORD:-redis-password}"
-      SPRING_DATA_REDIS_CONNECT_TIMEOUT: "${REDIS_SERVER_CONNECT_TIMEOUT:-5s}"
+      # --- VALKEY (formerly Redis) ---
+      SPRING_DATA_VALKEY_HOST: "${VALKEY_SERVER_HOSTNAME:-valkey}"
+      SPRING_DATA_VALKEY_PORT: "${VALKEY_SERVER_PORT:-6379}"
+      SPRING_DATA_VALKEY_PASSWORD: "${VALKEY_PASSWORD:-}"
+      SPRING_DATA_VALKEY_CONNECT_TIMEOUT: "${VALKEY_SERVER_CONNECT_TIMEOUT:-5s}"
 
       # --- LOGGING ---
       LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_CLOUD_GATEWAY: "DEBUG"