test(android/library): stub SyncController.lastSyncError with a real StateFlow

The VM now combines lastSyncError into uiState; a relaxed-mock flow
never emits, so the combine never fired and the state sat at Loading.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TsF3cNoKrqCYsU78cXC8U6

android/app/src/test/java/com/fabledsword/minstrel/library/ui/LibraryViewModelTest.kt

@@ -11,6 +11,7 @@ import com.fabledsword.minstrel.testutil.MainDispatcherExtension
 import io.mockk.every
 import io.mockk.mockk
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.test.runTest
@@ -21,6 +22,13 @@ import kotlin.test.assertEquals
 @ExtendWith(MainDispatcherExtension::class)
 class LibraryViewModelTest {
 
+    // lastSyncError needs a real StateFlow: the VM combines it into uiState,
+    // and a relaxed-mock flow never emits, so the combine would never fire.
+    private fun syncControllerMock(): SyncController =
+        mockk<SyncController>(relaxed = true) {
+            every { lastSyncError } returns MutableStateFlow(null)
+        }
+
     @Test
     fun `initial state is Loading before any DAO emission`() = runTest {
         val repo = mockk<LibraryRepository>()
@@ -29,7 +37,7 @@ class LibraryViewModelTest {
 
         val vm = LibraryViewModel(
             repo,
-            mockk<SyncController>(relaxed = true),
+            syncControllerMock(),
             mockk<PlayerController>(relaxed = true),
         )
 
@@ -51,7 +59,7 @@ class LibraryViewModelTest {
 
         val vm = LibraryViewModel(
             repo,
-            mockk<SyncController>(relaxed = true),
+            syncControllerMock(),
             mockk<PlayerController>(relaxed = true),
         )
 
@@ -71,7 +79,7 @@ class LibraryViewModelTest {
 
         val vm = LibraryViewModel(
             repo,
-            mockk<SyncController>(relaxed = true),
+            syncControllerMock(),
             mockk<PlayerController>(relaxed = true),
         )
 
@@ -94,7 +102,7 @@ class LibraryViewModelTest {
 
         val vm = LibraryViewModel(
             repo,
-            mockk<SyncController>(relaxed = true),
+            syncControllerMock(),
             mockk<PlayerController>(relaxed = true),
         )