feat: integrate new desktop shell and extend backend & ADRs

- Added `meldestelle-desktop` module using JVM/Compose Desktop, registered in `settings.gradle.kts`.
- Integrated new screens and desktop navigation into core: `Veranstaltungen`, `TurnierDetail`, etc.
- Expanded backend with `ExposedFunktionaerRepository` in `officials-infrastructure`.
- Completed ADRs for bounded context mapping (`ADR-0014`) and context map (`ADR-0015`).
- Updated and extended project documentation with session logs and architecture decisions.

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

frontend/core/navigation/src/commonMain/kotlin/at/mocode/frontend/core/navigation/AppScreen.kt

@@ -14,6 +14,21 @@ sealed class AppScreen(val route: String) {
   data object OrganizerProfile : AppScreen("/organizer/profile")
   data object AuthCallback : AppScreen("/auth/callback")
   data object Nennung : AppScreen("/nennung")
+
+  // --- Desktop-Navigation (Vision_03) ---
+  data object Veranstaltungen : AppScreen("/veranstaltungen")
+  data class VeranstaltungDetail(val id: Long) : AppScreen("/veranstaltung/$id")
+  data object VeranstaltungNeu : AppScreen("/veranstaltung/neu")
+  data class TurnierDetail(val veranstaltungId: Long, val turnierId: Long) :
+    AppScreen("/veranstaltung/$veranstaltungId/turnier/$turnierId")
+
+  data class TurnierNeu(val veranstaltungId: Long) : AppScreen("/veranstaltung/$veranstaltungId/turnier/neu")
+  data object Reiter : AppScreen("/reiter")
+  data object Pferde : AppScreen("/pferde")
+  data object Funktionaere : AppScreen("/funktionaere")
+  data object Meisterschaften : AppScreen("/meisterschaften")
+  data object Cups : AppScreen("/cups")
+
   companion object {
     fun fromRoute(route: String): AppScreen {
       return when (route) {
@@ -27,6 +42,13 @@ sealed class AppScreen(val route: String) {
         "/organizer/profile" -> OrganizerProfile
         "/auth/callback" -> AuthCallback
         "/nennung" -> Nennung
+        "/veranstaltungen" -> Veranstaltungen
+        "/veranstaltung/neu" -> VeranstaltungNeu
+        "/reiter" -> Reiter
+        "/pferde" -> Pferde
+        "/funktionaere" -> Funktionaere
+        "/meisterschaften" -> Meisterschaften
+        "/cups" -> Cups
         else -> Landing // Default fallback
       }
     }