refactor: narrow ViewModel injections, add ConnectionAware, delete dead code, integration tests

ViewModel Narrowing:
- V1: Created ConnectionAware interface; MessageSender, DeviceAdmin, DeviceControl extend it
- V2: Narrowed 6 ViewModels/actions to focused sub-interfaces (DeviceAdmin, MessageSender, DataRequester, DeviceControl)

Cleanup:
- C1: Deleted dead MeshDataMapper and its DI registration

Integration Tests:
- T2: SdkStateBridgeTest verifying WentOffline/CameOnline presence handling
- Verified Koin resolution, full test suite passes

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/channel/ChannelViewModel.kt

@@ -22,7 +22,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.koin.core.annotation.KoinViewModel
 import org.meshtastic.core.common.util.CommonUri
-import org.meshtastic.core.model.RadioController
+import org.meshtastic.core.model.DeviceAdmin
 import org.meshtastic.core.model.util.toChannelSet
 import org.meshtastic.core.repository.DataPair
 import org.meshtastic.core.repository.PlatformAnalytics
@@ -37,7 +37,7 @@ import org.meshtastic.proto.LocalConfig
 
 @KoinViewModel
 class ChannelViewModel(
-    private val radioController: RadioController,
+    private val radioController: DeviceAdmin,
     private val radioConfigRepository: RadioConfigRepository,
     private val analytics: PlatformAnalytics,
 ) : ViewModel() {