feat: Implement airport connection fetching and filtering

This commit introduces the functionality to fetch available flight connections for a selected origin airport and filter the destination airport list accordingly.

Key changes:
- Added `GetConnectionsForAirportUseCase` interface in `domain/stations` to define the contract for fetching airport connections.
- Implemented `GetConnectionsForAirportUseCaseImpl` in `model/repository` to fetch routes from the `RoutesService` and map them to domain `Airport` types.
- Created `AirportDomainMapper.kt` in `model/repository/mappers` to map `RouteResponse` and its nested types to domain `Airport` and `MacCity` types.
- Added a Hilt module `GetConnectionsForAirportUseCaseModule` to provide the implementation for `GetConnectionsForAirportUseCase`.
- Renamed `OriginAirportsUiState` to `AirportsUiState` in `StationsScreen.kt` and `StationsScreenViewModel.kt` for better generality.
- Updated `StationsScreenViewModel`:
    - Injected `GetConnectionsForAirportUseCase`.
    - Added `_availableDestinationsCodes` StateFlow to hold the codes of airports reachable from the selected origin.
    - Modified `airportsUiState` (previously `originAirportsUiState`) to take `filterDestinations` as a parameter and filter airports based on both search query and available destination codes.
    - Added `AirportInfo.toDepartureAirPort()` extension function.
- Updated `StationsScreen.kt` to use the renamed `AirportsUiState`.

model/repository/src/main/kotlin/dev/adriankuta/flights/model/repository/di/GetConnectionsForAirportUseCaseModule.kt

@@ -0,0 +1,19 @@
+package dev.adriankuta.flights.model.repository.di
+
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import dev.adriankuta.flights.domain.stations.GetConnectionsForAirportUseCase
+import dev.adriankuta.flights.model.repository.usecases.GetConnectionsForAirportUseCaseImpl
+
+@Module
+@InstallIn(SingletonComponent::class)
+@Suppress("UnnecessaryAbstractClass")
+internal abstract class GetConnectionsForAirportUseCaseModule {
+
+    @Binds
+    abstract fun bind(
+        getConnectionsForAirportUseCaseImpl: GetConnectionsForAirportUseCaseImpl,
+    ): GetConnectionsForAirportUseCase
+}

model/repository/src/main/kotlin/dev/adriankuta/flights/model/repository/mappers/AirportDomainMapper.kt

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+package dev.adriankuta.flights.model.repository.mappers
+
+import dev.adriankuta.flights.domain.types.Airport
+import dev.adriankuta.flights.domain.types.MacCity
+import dev.adriankuta.model.data.api.entities.RouteResponse
+
+fun RouteResponse.Airport.MacCity.toDomain(): MacCity? {
+    val macCode = macCode ?: return null
+    return MacCity(macCode = macCode)
+}
+
+fun RouteResponse.toDomain(): List<Airport> {
+    val departureAirportDomain = departureAirport?.let {
+        Airport.Departure(
+            code = it.code ?: return@let null,
+            name = it.name ?: return@let null,
+            macCity = departureAirport?.macCity?.toDomain(),
+        )
+    }
+    val arrivalAirportDomain = arrivalAirport?.let {
+        Airport.Arrival(
+            code = it.code ?: return@let null,
+            name = it.name ?: return@let null,
+            macCity = arrivalAirport?.macCity?.toDomain(),
+        )
+    }
+    val connectingAirportDomain = connectingAirport?.let {
+        Airport.Connecting(
+            code = it.code ?: return@let null,
+            name = it.name ?: return@let null,
+            macCity = connectingAirport?.macCity?.toDomain(),
+        )
+    }
+    return listOfNotNull(departureAirportDomain, arrivalAirportDomain, connectingAirportDomain)
+}

model/repository/src/main/kotlin/dev/adriankuta/flights/model/repository/usecases/GetConnectionsForAirportUseCaseImpl.kt

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+package dev.adriankuta.flights.model.repository.usecases
+
+import dev.adriankuta.flights.domain.stations.GetConnectionsForAirportUseCase
+import dev.adriankuta.flights.domain.types.Airport
+import dev.adriankuta.flights.model.repository.mappers.toDomain
+import dev.adriankuta.model.data.api.RoutesService
+import javax.inject.Inject
+
+internal class GetConnectionsForAirportUseCaseImpl @Inject constructor(
+    private val routesService: RoutesService,
+) : GetConnectionsForAirportUseCase {
+    override suspend fun invoke(airport: Airport): Set<Airport> {
+        val result = routesService.getRoutes(
+            languageCode = "pl",
+            departureAirportCode = airport.code,
+        )
+        return result.map { it.toDomain() }.flatten().toSet()
+    }
+}