feat(core+frontend): integrate mDNS-based network discovery and update UI

- **Network Discovery Service:**
  - Added platform-specific `DiscoveryModule` with JmDNS-based `JmDnsDiscoveryService` for JVM and no-op implementation for JS.
  - Implemented service and device discovery using mDNS to enable peer-to-peer synchronization within LAN.
  - Registered the module in Koin for dependency injection and integrated it with `networkModule`.

- **Frontend Integration:**
  - Enhanced `BewerbViewModel` with intents and actions for starting, stopping, and refreshing network scans.
  - Introduced polling for discovered services during an active scan.

- **UI Additions:**
  - Added a `NetworkDiscoveryPanel` in `TurnierBewerbeTab` to display discovered services and indicate scan state.
  - Updated action buttons to include toggle functionality for network scans.

gradle/libs.versions.toml

@@ -74,6 +74,7 @@ keycloakAdminClient = "26.0.7"
 
 # Utilities
 bignum = "0.3.10"
+jmdns = "3.5.12"
 logback = "1.5.25"
 caffeine = "3.2.3"
 reactorKafka = "1.3.23"
@@ -260,6 +261,7 @@ reactor-kafka = { module = "io.projectreactor.kafka:reactor-kafka", version.ref
 jackson-module-kotlin = { module = "com.fasterxml.jackson.module:jackson-module-kotlin" }
 jackson-datatype-jsr310 = { module = "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" }
 jakarta-annotation-api = { module = "jakarta.annotation:jakarta.annotation-api", version.ref = "jakartaAnnotation" }
+jmdns = { module = "org.jmdns:jmdns", version.ref = "jmdns" }
 
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junitJupiter" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junitJupiter" }