refactor: remove Dockerfile syntax directives to simplify and standardize definitions

Removed `# syntax=docker/dockerfile:1.8` from various Dockerfiles as it is no longer needed. Updated `.gitea/workflows/docker-publish.yaml` to enhance ARM64 build reliability with host driver enforcement and commented out unused caching configurations for clarity.

.gitea/workflows/docker-publish.yaml

@@ -80,10 +80,17 @@ jobs:
           chmod +x gradlew
           ./gradlew :frontend:shells:meldestelle-portal:jsBrowserDistribution -Pproduction=true --no-daemon
 
-      # OPTIMIERUNG: QEMU entfernt, da der Runner nativ auf ARM64 (Zora) läuft.
-      # Docker Buildx für effizienten Build-Support
+        # OPTIMIERUNG: QEMU entfernt, da der Runner nativ auf ARM64 (Zora) läuft.
+        # Docker Buildx für effizienten Build-Support
+        #      - name: Set up Docker Buildx
+        #        uses: docker/setup-buildx-action@v3
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          # Wir erzwingen die Nutzung des Host-Drivers,
+          # um gRPC-Abstürze im Container-Builder zu vermeiden
+          driver: docker
 
       # Login bei deiner Gitea Registry
       - name: Log in to the Container registry
@@ -121,7 +128,7 @@ jobs:
             JAVA_VERSION=${{ env.JAVA_VERSION }}
             KEYCLOAK_IMAGE_TAG=26.4
             JVM_OPTS_APPEND=${{ env.JVM_OPTS_ARM64 }}
-          # KORREKTUR: 'inline' Cache statt 'gha' für Gitea-Kompatibilität
-          cache-from: type=inline
-          cache-to: type=inline,mode=max
+#          # KORREKTUR: 'inline' Cache statt 'gha' für Gitea-Kompatibilität
+#          cache-from: type=inline
+#          cache-to: type=inline,mode=max
 

backend/infrastructure/gateway/Dockerfile

@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:1.8
-
 # ===================================================================
 # Multi-stage Dockerfile for Meldestelle API Gateway
 # Features: Security hardening, monitoring support, optimal caching, BuildKit cache mounts

backend/services/entries/Dockerfile

@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:1.8
-
 # ===================================================================
 # Multi-stage Dockerfile for Meldestelle Entries Service
 # ===================================================================

backend/services/ping/Dockerfile

@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:1.8
-
 # ===================================================================
 # Multi-stage Dockerfile for Meldestelle Ping Service
 # Features: Security hardening, monitoring support, optimal caching, BuildKit cache mounts

backend/services/results/results-service/Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.8
 ARG GRADLE_VERSION
 ARG JAVA_VERSION
 ARG BUILD_DATE

backend/services/scheduling/scheduling-service/Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.8
 ARG GRADLE_VERSION
 ARG JAVA_VERSION
 ARG BUILD_DATE

config/docker/caddy/web-app/Dockerfile

@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:1.8
-
 # ===================================================================
 # Dockerfile for Meldestelle Web-App (Hybrid Build)
 # Version: 3.2.0 - Optimized & Cleaned

config/docker/keycloak/Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.8
 # ===================================================================
 # Production-Ready Keycloak Dockerfile
 # ===================================================================

config/docker/nginx/web-app/Dockerfile

@@ -1,4 +1,3 @@
-# syntax=docker/dockerfile:1.8
 # ===================================================================
 # Multi-Stage Dockerfile for Meldestelle Web-App (Kotlin/JS)
 # Version: 2.3.1 - Optimized for Production Build (No Source Maps)