refactor: Migrate from monolithic to modular architecture

- Restructure project into domain-specific modules (core, masterdata, members, horses, events, infrastructure)
- Create shared client components in common-ui module
- Implement CI/CD workflows with GitHub Actions
- Consolidate documentation in docs directory
- Remove deprecated modules and documentation files
- Add cleanup and migration scripts for transition
- Update README with new project structure and setup instructions

settings.gradle.kts

@@ -44,13 +44,59 @@ dependencyResolutionManagement {
     }
 }
 
-// Self-Contained Systems modules
-include(":shared-kernel")
-include(":master-data")
-include(":member-management")
-include(":horse-registry")
-include(":event-management")
-include(":api-gateway")
+// Platform modules
+include(":platform:platform-bom")
+include(":platform:platform-dependencies")
+include(":platform:platform-testing")
 
-// Frontend module
-include(":composeApp")
+// Core modules
+include(":core:core-domain")
+include(":core:core-utils")
+
+// Members modules
+include(":members:members-domain")
+include(":members:members-application")
+include(":members:members-infrastructure")
+include(":members:members-api")
+include(":members:members-service")
+
+// Horses modules
+include(":horses:horses-domain")
+include(":horses:horses-application")
+include(":horses:horses-infrastructure")
+include(":horses:horses-api")
+include(":horses:horses-service")
+
+// Events modules
+include(":events:events-domain")
+include(":events:events-application")
+include(":events:events-infrastructure")
+include(":events:events-api")
+include(":events:events-service")
+
+// Masterdata modules
+include(":masterdata:masterdata-domain")
+include(":masterdata:masterdata-application")
+include(":masterdata:masterdata-infrastructure")
+include(":masterdata:masterdata-api")
+include(":masterdata:masterdata-service")
+
+// Infrastructure modules
+include(":infrastructure:gateway")
+include(":infrastructure:auth:auth-client")
+include(":infrastructure:auth:auth-server")
+include(":infrastructure:messaging:messaging-client")
+include(":infrastructure:messaging:messaging-config")
+include(":infrastructure:cache:cache-api")
+include(":infrastructure:cache:redis-cache")
+include(":infrastructure:event-store:event-store-api")
+include(":infrastructure:event-store:redis-event-store")
+include(":infrastructure:monitoring:monitoring-client")
+include(":infrastructure:monitoring:monitoring-server")
+
+// Client modules
+include(":client:common-ui")
+include(":client:web-app")
+include(":client:desktop-app")
+
+// Legacy modules have been removed after successful migration