M7g: feature cleanups after the design-system fix pass

Resource-backed snackbars (showKvittSnackbar) in account, onboarding and
settings; SettingsScaffold replaced by KvittScaffold + SettingsMessageEffect.
KvittButton(loading) for S-6 saving and S-16 Synka nu. S-10 missing state
disables Synka nu offline (connectivity in the ViewModel, new
detail_missing_offline goldens). S-6 system back asks to discard unsaved
changes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQd3pEP9UeN2uifbHknQ7B

android/feature/settle/src/main/kotlin/se/hagstedt/kvitt/feature/settle/SettlementDetailScreen.kt

@@ -123,7 +123,8 @@ fun SettlementDetailContent(
                         action = stringResource(R.string.settle_detail_sync_now),
                         actionIcon = KvittIcon.Sync,
                         actionKind = ButtonKind.Tonal,
-                        onAction = actions::onSyncNow,
+                        actionEnabled = state.online,
+                        onAction = { if (state.online) actions.onSyncNow() },
                     )
                     else -> DetailBody(state, detail)
                 }

android/feature/settle/src/main/kotlin/se/hagstedt/kvitt/feature/settle/SettlementDetailViewModel.kt

@@ -16,6 +16,7 @@ import se.hagstedt.kvitt.model.Account
 import se.hagstedt.kvitt.model.AccountId
 import se.hagstedt.kvitt.model.AccountRepository
 import se.hagstedt.kvitt.model.AuditAction
+import se.hagstedt.kvitt.model.ConnectivityRepository
 import se.hagstedt.kvitt.model.HomeRepository
 import se.hagstedt.kvitt.model.SettlementDetailState
 import se.hagstedt.kvitt.model.SettlementId
@@ -25,7 +26,8 @@ import se.hagstedt.kvitt.model.TimelineLine
 import se.hagstedt.kvitt.model.User
 
 /**
- * Everything S-10 shows. [detail] null after loading is the missing state (the S-8 missing layout, design-spec S-10).
+ * Everything S-10 shows. [detail] null after loading is the missing state (the S-8 missing layout, design-spec S-10);
+ * its "Synka nu" needs [online].
  */
 data class SettlementDetailUiState(
     val loading: Boolean = true,
@@ -35,6 +37,7 @@ data class SettlementDetailUiState(
     val accounts: List<Account> = emptyList(),
     val confirmDelete: Boolean = false,
     val deletedByMe: Boolean = false,
+    val online: Boolean = true,
 ) {
     /** Design-spec §2.4: an account's colour is its position in `AccountRepository.all()`. */
     fun colorIndex(id: AccountId): Int = accounts.indexOfFirst { it.id == id }.coerceAtLeast(0)
@@ -61,6 +64,7 @@ class SettlementDetailViewModel @javax.inject.Inject constructor(
     private val settlements: SettlementRepository,
     accounts: AccountRepository,
     home: HomeRepository,
+    connectivity: ConnectivityRepository,
     private val sync: SyncRepository,
 ) : ViewModel(), SettlementDetailActions {
     val id: SettlementId? = savedStateHandle.get<String>(SettleArgs.SETTLEMENT_ID)?.let(::SettlementId)
@@ -70,9 +74,10 @@ class SettlementDetailViewModel @javax.inject.Inject constructor(
         id?.let { settlements.detail(it) } ?: flowOf(null),
         accounts.all(),
         home.home(),
+        connectivity.online,
         local,
-    ) { detail, all, h, l ->
-        l.copy(loading = false, detail = detail, accounts = all, me = h.me, partner = h.partner)
+    ) { detail, all, h, online, l ->
+        l.copy(loading = false, detail = detail, accounts = all, me = h.me, partner = h.partner, online = online)
     }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(STOP_TIMEOUT_MS), SettlementDetailUiState())
 
     override fun onDelete() = local.update { it.copy(confirmDelete = true) }

android/feature/settle/src/test/kotlin/se/hagstedt/kvitt/feature/settle/SettlementDetailViewModelTest.kt

@@ -30,7 +30,7 @@ class SettlementDetailViewModelTest {
     fun reset() = Dispatchers.resetMain()
 
     private fun vm(id: String, repos: FakeRepositories = FakeRepositories(SettleScenarios.detail)) =
-        SettlementDetailViewModel(SavedStateHandle(mapOf(SettleArgs.SETTLEMENT_ID to id)), repos.settlements, repos.accounts, repos.home, repos.sync)
+        SettlementDetailViewModel(SavedStateHandle(mapOf(SettleArgs.SETTLEMENT_ID to id)), repos.settlements, repos.accounts, repos.home, repos.connectivity, repos.sync)
 
     @Test
     fun loadedShowsTheSettlementAndItsActions() = runTest {
@@ -48,6 +48,14 @@ class SettlementDetailViewModelTest {
         assertFalse(s.actions)
     }
 
+    @Test
+    fun missingOfflineCarriesTheConnectivityForSyncNow() = runTest {
+        assertTrue(vm(SettleScenarios.missing.value).state.first { !it.loading }.online)
+        val offline = vm(SettleScenarios.missing.value, FakeRepositories(SettleScenarios.detailOffline)).state.first { !it.loading }
+        assertNull(offline.detail)
+        assertFalse(offline.online)
+    }
+
     @Test
     fun deletedHasTheDeletionLineAndNoActions() = runTest {
         val s = vm(SettleScenarios.deleted.value).state.first { !it.loading }

android/feature/settle/src/test/kotlin/se/hagstedt/kvitt/feature/settle/screenshot/SettleScreenshotTest.kt

@@ -78,6 +78,7 @@ private val cases: Map<String, Case> = linkedMapOf(
     "detail_offline" to Detail(SettleScenarios.detailOffline, SettleScenarios.split.value),
     "detail_delete_dialog" to Detail(SettleScenarios.detail, SettleScenarios.swish.value) { onDelete() },
     "detail_missing" to Detail(SettleScenarios.detail, SettleScenarios.missing.value),
+    "detail_missing_offline" to Detail(SettleScenarios.detailOffline, SettleScenarios.missing.value),
     "detail_long" to Detail(SettleScenarios.longDetail, SettleScenarios.long.value, height = longHeight),
 )
 
@@ -105,7 +106,7 @@ class SettleScreenshotTest(private val name: String) {
             is Detail -> {
                 val repos = FakeRepositories(case.scenario)
                 val vm = SettlementDetailViewModel(
-                    SavedStateHandle(mapOf(SettleArgs.SETTLEMENT_ID to case.id)), repos.settlements, repos.accounts, repos.home, repos.sync,
+                    SavedStateHandle(mapOf(SettleArgs.SETTLEMENT_ID to case.id)), repos.settlements, repos.accounts, repos.home, repos.connectivity, repos.sync,
                 )
                 vm.apply(case.steps)
                 ScreenSnapshots.snap(compose, name, case.height, case.largeFont) {