chore(gateway, ping-service, security): streamline configurations, remove redundancies, and improve resilience

- Removed `MdcCorrelationFilter` and simplified correlation ID management using Micrometer Tracing.
- Updated `SecurityConfig` in `gateway` with enhanced role-based access and standardized JWT validation.
- Added new `@Profile` annotations in `ping-service` to exclude certain components during testing.
- Refactored and removed legacy `application-keycloak.yaml` and consolidated settings into the primary `application.yaml`.
- Adjusted Gradle scripts to clean up dependency declarations and improve modularity.
- Simplified CORS and Gateway route configurations for better maintainability.

backend/infrastructure/gateway/build.gradle.kts

@@ -1,72 +1,50 @@
 import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 
-// Dieses Modul ist das API-Gateway und der einzige öffentliche Einstiegspunkt
-// für alle externen Anfragen an das Meldestelle-System.
 plugins {
   alias(libs.plugins.kotlinJvm)
   alias(libs.plugins.kotlinSpring)
-  alias(libs.plugins.kotlinJpa)
   alias(libs.plugins.spring.boot)
 }
 
-// Konfiguriert die Hauptklasse für das ausführbare JAR
 springBoot {
   mainClass.set("at.mocode.infrastructure.gateway.GatewayApplicationKt")
 }
 
 dependencies {
-  // Wiederherstellung des Standardzustands: Das Gateway verwendet das reparierte lokale BOM.
   implementation(platform(projects.platform.platformBom))
 
-  // === Core Dependencies ===
   implementation(projects.core.coreUtils)
   implementation(projects.platform.platformDependencies)
   implementation(projects.backend.infrastructure.monitoring.monitoringClient)
-  implementation(projects.backend.infrastructure.security) // NEU: Security Module
+
+  // Wir nutzen das Security-Modul NICHT direkt, um Servlet-Abhängigkeiten zu vermeiden.
+  // Stattdessen definieren wir die benötigten Reactive-Dependencies hier explizit.
+  // implementation(projects.backend.infrastructure.security)
 
   // === GATEWAY-SPEZIFISCHE ABHÄNGIGKEITEN ===
-  // Die WebFlux-Abhängigkeit wird jetzt korrekt durch das BOM bereitgestellt.
   implementation(libs.spring.boot.starter.webflux)
-
-  // Kern-Gateway inkl. Security, Actuator, CircuitBreaker, Discovery
-  // implementation(libs.bundles.gateway.core)
   implementation(libs.spring.cloud.starter.gateway.server.webflux)
   implementation(libs.spring.cloud.starter.consul.discovery)
   implementation(libs.spring.boot.starter.actuator)
-  // Security dependencies are now transitively provided by infrastructure.security,
-  // but Gateway is WebFlux, so we might need specific WebFlux security if the shared module is WebMVC only.
-  // However, starter-security works for both. Resource server might need check.
-  // For now, we keep explicit dependencies if they differ from the shared module or just rely on shared.
-  // Shared module has: starter-security, starter-oauth2-resource-server, jose, web.
-  // Gateway needs: starter-security, starter-oauth2-resource-server, jose.
-  // "web" (MVC) vs "webflux" (Reactive) conflict might occur if shared module pulls in MVC.
-  // CHECK: Shared module uses `implementation(libs.spring.web)`. This pulls in spring-webmvc usually?
-  // No, `spring-web` is common. `spring-boot-starter-web` pulls in MVC.
-  // The shared module build.gradle.kts uses `libs.spring.web`.
+
+  // Security (Reactive)
+  implementation(libs.spring.boot.starter.security)
+  implementation(libs.spring.boot.starter.oauth2.resource.server)
+  implementation(libs.spring.security.oauth2.jose)
 
   implementation(libs.spring.cloud.starter.circuitbreaker.resilience4j)
 
-  // Ergänzende Observability (Logging, Jackson)
-  // implementation(libs.bundles.gateway.observability)
   implementation(libs.kotlin.logging.jvm)
   implementation(libs.logback.classic)
   implementation(libs.logback.core)
   implementation(libs.jackson.module.kotlin)
   implementation(libs.jackson.datatype.jsr310)
 
-  // Redis-Unterstützung für verteiltes Rate Limiting (RequestRateLimiter)
-  // implementation(libs.bundles.gateway.redis)
   implementation(libs.spring.boot.starter.data.redis)
 
-  // === Tracing Dependencies (Micrometer Tracing) ===
-  // Ermöglicht verteiltes Tracing über Thread-Grenzen hinweg (ersetzt manuellen MDC-Filter)
   implementation(libs.micrometer.tracing.bridge.brave)
-  // Optional: Zipkin Reporter, falls du Traces an Zipkin senden willst (bereits im monitoringClient enthalten, aber hier explizit schadet nicht)
-  // implementation(libs.zipkin.reporter.brave)
 
-  // === Test Dependencies ===
   testImplementation(projects.platform.platformTesting)
-  // testImplementation(libs.bundles.testing.jvm)
   testImplementation(libs.junit.jupiter.api)
   testImplementation(libs.junit.jupiter.engine)
   testImplementation(libs.junit.jupiter.params)
@@ -80,7 +58,6 @@ tasks.test {
   useJUnitPlatform()
 }
 
-// Konfiguration für Integration Tests
 sourceSets {
   val integrationTest by creating {
     compileClasspath += sourceSets.main.get().output