feat(reiter-feature): introduce Reiter management module with screens, ViewModel, and domain models

- Added `reiter-feature` module for managing riders, including list and detail views.
- Implemented `MsMasterDetailLayout` for ReiterScreen, integrating `MsDataTable`, `MsFilterBar`, and `MsActionToolbar`.
- Defined domain models (`Reiter`, `LizenzKlasse`, `Sparte`, `ReiterStatus`) with mock data support.
- Updated roadmap to reflect progress in Phase 5: Routing & Screen-Komposition.
- Registered the new module in `settings.gradle.kts`.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

frontend/features/reiter-feature/build.gradle.kts

@@ -0,0 +1,30 @@
+/**
+ * Feature-Modul: Reiter-Verwaltung (Desktop-only)
+ */
+plugins {
+  alias(libs.plugins.kotlinMultiplatform)
+  alias(libs.plugins.composeMultiplatform)
+  alias(libs.plugins.composeCompiler)
+}
+group = "at.mocode.clients"
+version = "1.0.0"
+kotlin {
+  jvm()
+  sourceSets {
+    jvmMain.dependencies {
+      implementation(projects.frontend.core.designSystem)
+      implementation(projects.frontend.core.domain)
+      implementation(projects.frontend.core.navigation)
+      implementation(compose.desktop.currentOs)
+      implementation(compose.foundation)
+      implementation(compose.runtime)
+      implementation(compose.material3)
+      implementation(compose.ui)
+      implementation(compose.materialIconsExtended)
+      implementation(libs.bundles.kmp.common)
+      implementation(libs.koin.core)
+      implementation(libs.koin.compose)
+      implementation(libs.koin.compose.viewmodel)
+    }
+  }
+}