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/onboarding/src/main/kotlin/se/hagstedt/kvitt/feature/onboarding/PairingScreen.kt

@@ -15,7 +15,6 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.SnackbarDuration
 import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -27,6 +26,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalClipboard
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.LiveRegionMode
@@ -46,6 +46,7 @@ import se.hagstedt.kvitt.design.component.InviteCodeField
 import se.hagstedt.kvitt.design.component.KvittIconImage
 import se.hagstedt.kvitt.design.component.KvittScaffold
 import se.hagstedt.kvitt.design.component.KvittTextField
+import se.hagstedt.kvitt.design.component.showKvittSnackbar
 import se.hagstedt.kvitt.design.icon.KvittIcon
 import se.hagstedt.kvitt.design.theme.KvittDimens
 
@@ -113,14 +114,15 @@ fun PairingContent(
     snackbarHostState: SnackbarHostState = remember { SnackbarHostState() },
 ) {
     val snackbarText = when (state.error) {
-        PairingError.AppTooOld -> stringResource(DesignR.string.error_app_too_old)
-        PairingError.Server -> stringResource(DesignR.string.error_server)
-        PairingError.Validation -> stringResource(DesignR.string.error_validation)
+        PairingError.AppTooOld -> DesignR.string.error_app_too_old
+        PairingError.Server -> DesignR.string.error_server
+        PairingError.Validation -> DesignR.string.error_validation
         else -> null
     }
+    val resources = LocalResources.current
     LaunchedEffect(snackbarText) {
         if (snackbarText != null) {
-            snackbarHostState.showSnackbar(snackbarText, duration = SnackbarDuration.Short)
+            snackbarHostState.showKvittSnackbar(resources, snackbarText)
             actions.onErrorShown()
         }
     }

android/feature/onboarding/src/main/kotlin/se/hagstedt/kvitt/feature/onboarding/ProfileStepScreen.kt

@@ -22,7 +22,6 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.SnackbarDuration
 import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
@@ -33,6 +32,7 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.clearAndSetSemantics
@@ -60,6 +60,7 @@ import se.hagstedt.kvitt.design.component.NeedsConnectionHint
 import se.hagstedt.kvitt.design.component.PersonAvatar
 import se.hagstedt.kvitt.design.component.ProvideHousehold
 import se.hagstedt.kvitt.design.component.kvittLanguage
+import se.hagstedt.kvitt.design.component.showKvittSnackbar
 import se.hagstedt.kvitt.design.format.KvittLanguage
 import se.hagstedt.kvitt.design.icon.KvittIcon
 import se.hagstedt.kvitt.design.theme.KvittDimens
@@ -130,10 +131,11 @@ fun ProfileStepContent(
     modifier: Modifier = Modifier,
     snackbarHostState: SnackbarHostState = remember { SnackbarHostState() },
 ) {
-    val message = state.message?.let { stringResource(it.text) }
+    val message = state.message?.text
+    val resources = LocalResources.current
     LaunchedEffect(message) {
         if (message != null) {
-            snackbarHostState.showSnackbar(message, duration = SnackbarDuration.Short)
+            snackbarHostState.showKvittSnackbar(resources, message)
             actions.onMessageShown()
         }
     }

android/feature/onboarding/src/main/kotlin/se/hagstedt/kvitt/feature/onboarding/WaitingScreen.kt

@@ -12,7 +12,6 @@ import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.SnackbarDuration
 import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.SnackbarResult
 import androidx.compose.material3.Text
@@ -22,6 +21,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.semantics
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
@@ -43,6 +43,7 @@ import se.hagstedt.kvitt.design.component.NeedsConnectionHint
 import se.hagstedt.kvitt.design.component.ProvideHousehold
 import se.hagstedt.kvitt.design.component.SegmentedGroup
 import se.hagstedt.kvitt.design.component.kvittLanguage
+import se.hagstedt.kvitt.design.component.showKvittSnackbar
 import se.hagstedt.kvitt.design.format.DateFormatter
 import se.hagstedt.kvitt.design.icon.KvittIcon
 import kotlin.time.Instant
@@ -83,12 +84,12 @@ fun WaitingContent(
     snackbarHostState: SnackbarHostState = remember { SnackbarHostState() },
 ) {
     val error = state.loadError?.let {
-        stringResource(if (it == "network") DesignR.string.common_could_not_reach_server else DesignR.string.error_server)
+        if (it == "network") DesignR.string.common_could_not_reach_server else DesignR.string.error_server
     }
-    val retry = stringResource(DesignR.string.common_retry)
+    val resources = LocalResources.current
     LaunchedEffect(error) {
         if (error != null) {
-            val result = snackbarHostState.showSnackbar(error, actionLabel = retry, duration = SnackbarDuration.Long)
+            val result = snackbarHostState.showKvittSnackbar(resources, error, action = DesignR.string.common_retry)
             actions.onErrorShown()
             if (result == SnackbarResult.ActionPerformed) actions.onRetry()
         }