feat(build): Refactor infrastructure modules and establish single source of truth

This commit introduces a major refactoring of the build system and the core infrastructure modules. The primary goal is to establish a strict "Single Source of Truth" for all dependencies using Gradle Version Catalogs and to create a clean, maintainable, and scalable foundation for all current and future services.

### 1. Centralized Dependency Management (`libs.versions.toml`)

- **Established Single Source of Truth:** All dependency versions are now exclusively managed in `gradle/libs.versions.toml`. Hardcoded versions have been removed from all build scripts.
- **Introduced Gradle Bundles:** To simplify module dependencies, several bundles have been created (e.g., `testing-jvm`, `redis-cache`, `spring-cloud-gateway`, `monitoring-client`). This drastically reduces boilerplate in the `build.gradle.kts` files and improves readability.
- **Cleaned up Aliases:** All library and plugin aliases have been standardized for consistency.

### 2. Infrastructure Module Refactoring

All infrastructure modules (`core`, `platform`, `auth`, `cache`, `event-store`, `messaging`, `monitoring`, `gateway`) have been refactored to align with the new dependency management strategy.

- **Simplified Build Scripts:** The `build.gradle.kts` for each module now uses the new bundles and aliases, making them significantly cleaner and easier to understand.
- **Consistent Structure:** The architecture of each module now clearly follows the Port-Adapter pattern where applicable (e.g., `cache-api`/`redis-cache`).
- **Standardized `platform-bom`:** The project's own Bill of Materials (`platform-bom`) now also includes the Spring Cloud BOM, ensuring version consistency for all Spring-related dependencies.

### 3. Added Infrastructure Documentation

To improve onboarding and architectural understanding, a dedicated `README-*.md` file has been created for each refactored infrastructure module:
- `README-CORE.md`
- `README-PLATFORM.md`
- `README-INFRA-AUTH.md`
- `README-INFRA-CACHE.md`
- `README-INFRA-EVENT-STORE.md`
- `README-INFRA-MESSAGING.md`
- `README-INFRA-MONITORING.md`
- `README-INFRA-GATEWAY.md`

These documents explain the purpose, architecture, and usage of each component within the system. This lays the groundwork for our "Tracer Bullet" development approach.

build.gradle.kts

@@ -1,124 +1,24 @@
-/*
 import java.util.Locale
 
+// Defines plugins that are available to all subprojects.
+// `apply false` means the plugin is not applied to the root project itself.
 plugins {
-    kotlin("jvm") version "2.1.21" apply false
-    kotlin("plugin.spring") version "2.1.21" apply false
-    id("org.springframework.boot") version "3.2.3" apply false
-    id("io.spring.dependency-management") version "1.1.4" apply false
-    base
-}
-
-allprojects {
-    group = "at.mocode.meldestelle"
-    version = "0.1.0-SNAPSHOT"
-}
-
-subprojects {
-    repositories {
-        mavenCentral()
-    }
-
-    // Enable dependency locking for all configurations
-    dependencyLocking {
-        lockAllConfigurations()
-    }
-
-    // Add task to write lock files
-    tasks.register("resolveAndLockAll") {
-        doFirst {
-            require(gradle.startParameter.isWriteDependencyLocks)
-        }
-        doLast {
-            configurations.filter {
-                // Only lock configurations that can be resolved
-                it.isCanBeResolved
-            }.forEach { it.resolve() }
-        }
-    }
-
-    // Configure Kotlin compiler options
-    tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
-        compilerOptions {
-            jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21)
-            freeCompilerArgs.add("-Xjsr305=strict")
-        }
-    }
-
-    // Configure parallel test execution
-    tasks.withType<Test>().configureEach {
-        useJUnitPlatform()
-        // Enable parallel test execution
-        maxParallelForks = (Runtime.getRuntime().availableProcessors() / 2).takeIf { it > 0 } ?: 1
-        // Optimize JVM args for tests
-        jvmArgs = listOf("-Xmx512m", "-XX:+UseG1GC")
-    }
-
-    // Define a custom integrationTest task
-    tasks.register<Test>("integrationTest") {
-        description = "Runs integration tests."
-        group = "verification"
-
-        // Use the same configuration as the test task
-        useJUnitPlatform()
-        maxParallelForks = (Runtime.getRuntime().availableProcessors() / 2).takeIf { it > 0 } ?: 1
-        jvmArgs = listOf("-Xmx512m", "-XX:+UseG1GC")
-
-        // Include all tests that have "Integration" in their name
-        include("** / *Integration*Test.kt")
-
-        // Exclude unit tests (but keep integration tests)
-        exclude("** / *Test.kt")
-        include("** / *IntegrationTest.kt")
-
-        // Set system properties for integration tests
-        systemProperty("spring.profiles.active", "integration-test")
-        systemProperty("redis.host", "localhost")
-        systemProperty("redis.port", "6379")
-
-        // Generate reports in a separate directory
-        reports {
-            html.required.set(true)
-            junitXml.required.set(true)
-        }
-
-        // This task should run after the regular test task
-        // We don't use mustRunAfter here to avoid reference issues
-    }
-}
-*/
-
-import java.util.Locale
-
-plugins {
-    // KORREKTUR: Wir entfernen die hartcodierten Versionen und verwenden stattdessen
-    // die Aliase aus dem Version Catalog. `apply false` bleibt, da die Plugins
-    // hier nur für die Unterprojekte deklariert werden.
     alias(libs.plugins.kotlin.jvm) apply false
     alias(libs.plugins.kotlin.multiplatform) apply false
     alias(libs.plugins.compose.multiplatform) apply false
     alias(libs.plugins.compose.compiler) apply false
-    base
 }
 
-//allprojects {
-//    group = "at.mocode.meldestelle"
-//    version = "0.1.0-SNAPSHOT"
-//
-//    repositories {
-//        mavenCentral()
-//        google() // Wichtig für Compose-Abhängigkeiten
-//    }
-//}
-
+// Common configuration for all subprojects in this build.
 subprojects {
-    // Konfigurationen, die für alle Untermodule gelten.
+    // Enforce Java 21 for all Kotlin compilation tasks.
     tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
         compilerOptions {
             jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21)
         }
     }
 
+    // Configure all test tasks to use the JUnit Platform (for JUnit 5).
     tasks.withType<Test>().configureEach {
         useJUnitPlatform()
     }