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>

core/ui/src/commonMain/kotlin/org/meshtastic/core/ui/qr/ScannedQrCodeViewModel.kt

@@ -18,7 +18,7 @@ package org.meshtastic.core.ui.qr
 
 import androidx.lifecycle.ViewModel
 import org.koin.core.annotation.KoinViewModel
-import org.meshtastic.core.model.RadioController
+import org.meshtastic.core.model.DeviceAdmin
 import org.meshtastic.core.repository.RadioConfigRepository
 import org.meshtastic.core.ui.util.getChannelList
 import org.meshtastic.core.ui.viewmodel.safeLaunch
@@ -31,7 +31,7 @@ import org.meshtastic.proto.LocalConfig
 @KoinViewModel
 class ScannedQrCodeViewModel(
     private val radioConfigRepository: RadioConfigRepository,
-    private val radioController: RadioController,
+    private val radioController: DeviceAdmin,
 ) : ViewModel() {
 
     val channels = radioConfigRepository.channelSetFlow.stateInWhileSubscribed(initialValue = ChannelSet())