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

client/common-ui/build.gradle.kts

@@ -0,0 +1,52 @@
+plugins {
+    kotlin("jvm")
+    id("org.springframework.boot") apply false
+    id("io.spring.dependency-management") apply false
+    id("org.jetbrains.compose") version "1.7.3"
+    id("org.jetbrains.kotlin.plugin.compose") version "2.1.20"
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+dependencies {
+    // Core dependencies
+    implementation(projects.core.coreDomain)
+    implementation(projects.core.coreUtils)
+
+    // Domain modules
+    implementation(projects.events.eventsDomain)
+    implementation(projects.horses.horsesDomain)
+    implementation(projects.masterdata.masterdataDomain)
+    implementation(projects.members.membersDomain)
+
+    // Compose dependencies for Desktop
+    implementation(compose.desktop.currentOs)
+    implementation(compose.runtime)
+    implementation(compose.foundation)
+    implementation(compose.material3)
+    implementation(compose.ui)
+    implementation(compose.components.resources)
+    implementation(compose.materialIconsExtended)
+
+    // AndroidX dependencies are provided by the Compose plugin
+
+    // Ktor Client dependencies
+    implementation(libs.ktor.client.core)
+    implementation(libs.ktor.client.cio)
+    implementation(libs.ktor.client.contentNegotiation)
+    implementation(libs.ktor.client.serializationKotlinxJson)
+
+    // Kotlinx dependencies
+    implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.6.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.3")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-swing:1.8.0")
+    implementation("com.benasher44:uuid:0.8.4")
+
+    // Testing
+    testImplementation(kotlin("test"))
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.8.0")
+}