chore(MP-23): network DI client, frontend architecture guards, detekt & ktlint setup, docs, ping DI factory (#21)

* chore(MP-21): snapshot pre-refactor state (Epic 1)

* chore(MP-22): scaffold new repo structure, relocate Docker Compose, move frontend/backend modules, update Makefile; add docs mapping and env template

* MP-22 Epic 2: Erfolgreich umgesetzt und verifiziert

* MP-23 Epic 3: Gradle/Build Governance zentralisieren

docker/.env.example

@@ -0,0 +1,43 @@
+# Core project name used as prefix for container names
+COMPOSE_PROJECT_NAME=meldestelle
+
+# Ports
+POSTGRES_PORT=5432:5432
+REDIS_PORT=6379:6379
+KC_PORT=8180:8080
+CONSUL_PORT=8500:8500
+PROMETHEUS_PORT=9090:9090
+GF_PORT=3000:3000
+WEB_APP_PORT=4000:80
+PING_SERVICE_PORT=8082:8082
+PING_DEBUG_PORT=5006:5006
+GATEWAY_PORT=8081:8081
+GATEWAY_DEBUG_PORT=5005:5005
+GATEWAY_SERVER_PORT=8081
+DESKTOP_APP_VNC_PORT=5900:5900
+DESKTOP_APP_NOVNC_PORT=6080:6080
+
+# Postgres
+POSTGRES_USER=meldestelle
+POSTGRES_PASSWORD=meldestelle
+POSTGRES_DB=meldestelle
+
+# Keycloak
+KC_ADMIN_USER=admin
+KC_ADMIN_PASSWORD=admin
+KC_HOSTNAME=localhost
+
+# PgAdmin
+PGADMIN_EMAIL=admin@example.com
+PGADMIN_PASSWORD=admin
+
+# Grafana
+GF_ADMIN_USER=admin
+GF_ADMIN_PASSWORD=admin
+
+# Docker build versions (optional overrides)
+DOCKER_GRADLE_VERSION=9.1.0
+DOCKER_JAVA_VERSION=21
+DOCKER_NODE_VERSION=22.21.0
+DOCKER_NGINX_VERSION=1.28.0-alpine
+WEB_BUILD_PROFILE=dev