feat(horses-service): remove legacy configuration and repository classes

- Deleted outdated `ApplicationConfiguration` and `HorseRepositoryImpl` classes.
- Migrated to streamlined modular Gradle configuration in `build.gradle.kts`.
- Updated domain models and dependencies to use multiplatform and serialization plugins.
- Added modular setup for `horses` namespace in `settings.gradle.kts`.
- Reorganized database configuration with minimal JDBC bindings for development.

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

backend/services/persons/persons-domain/build.gradle.kts

@@ -0,0 +1,26 @@
+plugins {
+  alias(libs.plugins.kotlinMultiplatform)
+  alias(libs.plugins.kotlinSerialization)
+}
+
+kotlin {
+  jvm()
+
+  sourceSets {
+    commonMain {
+      kotlin.srcDir("src/main/kotlin")
+      dependencies {
+        implementation(projects.core.coreDomain)
+        implementation(projects.core.coreUtils)
+        implementation(libs.kotlinx.datetime)
+        implementation(libs.kotlinx.serialization.json)
+      }
+    }
+    commonTest {
+      kotlin.srcDir("src/test/kotlin")
+      dependencies {
+        implementation(projects.platform.platformTesting)
+      }
+    }
+  }
+}

backend/services/persons/persons-domain/src/main/kotlin/at/mocode/persons/domain/model/DomPerson.kt

@@ -0,0 +1,58 @@
+@file:OptIn(kotlin.uuid.ExperimentalUuidApi::class)
+
+package at.mocode.persons.domain.model
+
+import at.mocode.core.domain.model.DatenQuelleE
+import at.mocode.core.domain.serialization.KotlinInstantSerializer
+import at.mocode.core.domain.serialization.UuidSerializer
+import kotlinx.datetime.LocalDate
+import kotlinx.serialization.Serializable
+import kotlin.time.Clock
+import kotlin.time.Instant
+import kotlin.uuid.Uuid
+
+/**
+ * Domain model representing a person (rider/member) in the registry system.
+ *
+ * @property personId Unique internal identifier (UUID).
+ * @property lizenzNummer ÖPS license number (from ZNS LIZENZ01.dat).
+ * @property nachname Last name.
+ * @property vorname First name.
+ * @property geschlecht Gender code (M/W).
+ * @property geburtsdatum Date of birth.
+ * @property nation Nation code (e.g. AUT).
+ * @property lizenzKlasse License class (e.g. R1, R2, RD2).
+ * @property mitgliedsNummer Membership number.
+ * @property vereinsNummer Club number.
+ * @property vereinsName Club name.
+ * @property datenQuelle Source of the data.
+ * @property createdAt Timestamp when this record was created.
+ * @property updatedAt Timestamp when this record was last updated.
+ */
+@Serializable
+data class DomPerson(
+  @Serializable(with = UuidSerializer::class)
+  val personId: Uuid = Uuid.random(),
+
+  val lizenzNummer: String,
+  val nachname: String,
+  val vorname: String,
+
+  val geschlecht: String? = null,
+  val geburtsdatum: LocalDate? = null,
+  val nation: String? = null,
+  val lizenzKlasse: String? = null,
+  val mitgliedsNummer: String? = null,
+  val vereinsNummer: String? = null,
+  val vereinsName: String? = null,
+
+  val istAktiv: Boolean = true,
+  val datenQuelle: DatenQuelleE = DatenQuelleE.IMPORT_ZNS,
+
+  @Serializable(with = KotlinInstantSerializer::class)
+  val createdAt: Instant = Clock.System.now(),
+  @Serializable(with = KotlinInstantSerializer::class)
+  var updatedAt: Instant = Clock.System.now()
+) {
+  fun getDisplayName(): String = "$vorname $nachname"
+}