feat: data source toggles + HTTP status codes (upstream #242)

Port upstream PR #242 data layer: per-source enabled toggles and HTTP
status codes for custom data sources.

- IRemoteSource: NetworkResult(code, stream) + getNetworkStream
- RemoteSource: return HTTP status code (200 ok / error code / ERR)
- ISettingsRepo: dataSourcesStatus StateFlow<Map<String,Int>>
- SettingsRepo: persist enabled flags (single JSON per key) + status
- DatabaseRepo: filter by enabled toggles, write back status codes
- Settings.kt: DataSourcesSettings + satelliteEnabled/transceiversEnabled
- Sync test fakes (AmSatRepositoryTest, DatabaseRepoTest, Fakes.kt)

Fork-specific features preserved: builtinTypesByUrl reverse lookup,
satnogs migration, map-type data source structure.

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/model/Settings.kt

@@ -68,8 +68,13 @@ data class OtherSettings(
 
 data class DataSourcesSettings(
     val satelliteUrls: List<String>,
-    val transceiversUrls: List<String>
-)
+    val transceiversUrls: List<String>,
+    val satelliteEnabled: List<Boolean> = emptyList(),
+    val transceiversEnabled: List<Boolean> = emptyList()
+) {
+    fun isSatelliteEnabled(index: Int): Boolean = satelliteEnabled.getOrElse(index) { true }
+    fun isTransceiverEnabled(index: Int): Boolean = transceiversEnabled.getOrElse(index) { true }
+}
 
 data class RadioControlSettings(
     val enabled: Boolean,

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISettingsRepo.kt

@@ -73,6 +73,11 @@ interface ISettingsRepo {
     fun updateDataSourcesSettings(settings: DataSourcesSettings)
     //endregion
 
+    //region # Data sources status
+    val dataSourcesStatus: StateFlow<Map<String, Int>>
+    fun updateDataSourcesStatus(status: Map<String, Int>)
+    //endregion
+
     //region # Radio control settings
     val radioControlSettings: StateFlow<RadioControlSettings>
     fun updateRadioControlSettings(settings: RadioControlSettings)

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/source/IRemoteSource.kt

@@ -19,9 +19,17 @@ package com.rtbishop.look4sat.core.domain.source
 
 import java.io.InputStream
 
+/** Result of a network download: the HTTP status code and the response body stream. */
+data class NetworkResult(val code: Int, val stream: InputStream?) {
+    companion object {
+        /** Code used when a request fails before any HTTP response is received. */
+        const val CONNECTION_ERROR = -1
+    }
+}
+
 interface IRemoteSource {
     suspend fun getFileStream(uri: String): InputStream?
-    suspend fun getNetworkStream(url: String): InputStream?
+    suspend fun getNetworkStream(url: String): NetworkResult
     suspend fun getAmSatCatalog(): String?
     suspend fun getAmSatReports(hours: Int, limit: Int): String?
     suspend fun submitAmSatReport(payloadJson: String): Pair<Int, String>?