fix: replace all remaining hardcoded German strings with stringResource

ModelSheet, ChatComponents, SettingsScreen had hardcoded strings like
"Ausgewählt", "Modell auswählen", "Zurück" etc. instead of using the
existing string resources. Now all UI text uses stringResource(R.string.xxx)
for proper de/en localization.

app/src/main/java/dev/kaizen/app/chat/ChatComponents.kt

@@ -318,7 +318,7 @@ fun ChatInput(
                         cursorBrush = SolidColor(accent.primary), maxLines = 6, modifier = Modifier.fillMaxWidth(),
                     )
                 }
-                GhostIconButton(Icons.Rounded.Call, "Anruf")
+                GhostIconButton(Icons.Rounded.Call, stringResource(R.string.chat_call))
                 Spacer(Modifier.width(4.dp))
                 val canSend = enabled && (value.isNotBlank() || pendingFiles.any { it.uploaded != null }) && pendingFiles.none { it.uploading }
                 SendButton(enabled = canSend, onClick = onSend)
@@ -365,14 +365,14 @@ private fun PendingFileChip(pf: PendingFile, onRemove: () -> Unit) {
         }
         if (pf.error != null) {
             Box(Modifier.fillMaxSize().background(Color(0xFFDC2626).copy(alpha = 0.3f)), contentAlignment = Alignment.Center) {
-                Icon(Icons.Rounded.Close, "Fehler", tint = Color.White, modifier = Modifier.size(18.dp))
+                Icon(Icons.Rounded.Close, stringResource(R.string.chat_error), tint = Color.White, modifier = Modifier.size(18.dp))
             }
         }
         Box(
             Modifier.align(Alignment.TopEnd).padding(2.dp).size(18.dp).clip(KaizenShapes.circle).background(Color.Black.copy(alpha = 0.5f)).clickable(onClick = onRemove),
             contentAlignment = Alignment.Center,
         ) {
-            Icon(Icons.Rounded.Close, "Entfernen", tint = Color.White, modifier = Modifier.size(12.dp))
+            Icon(Icons.Rounded.Close, stringResource(R.string.chat_remove), tint = Color.White, modifier = Modifier.size(12.dp))
         }
     }
 }

app/src/main/java/dev/kaizen/app/chat/ModelSheet.kt

@@ -21,6 +21,8 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import dev.kaizen.app.net.KaizenModel
+import dev.kaizen.app.R
+import androidx.compose.ui.res.stringResource
 import dev.kaizen.app.ui.theme.LocalKaizenAccent
 import dev.kaizen.app.haptics.rememberHaptics
 
@@ -66,14 +68,14 @@ private fun groupFor(m: KaizenModel): String = when {
     else -> "OpenRouter"
 }
 
-private fun buildGroups(models: List<KaizenModel>, favorites: Set<String>, query: String): List<ModelGroup> {
+private fun buildGroups(models: List<KaizenModel>, favorites: Set<String>, query: String, favoritesLabel: String = "★ Favorites"): List<ModelGroup> {
     val q = query.trim().lowercase()
     val filtered = if (q.isEmpty()) models
     else models.filter { it.name?.lowercase()?.contains(q) == true || it.id.lowercase().contains(q) }
 
     val groups = mutableListOf<ModelGroup>()
     val favs = filtered.filter { it.id in favorites }
-    if (favs.isNotEmpty()) groups += ModelGroup("★ Favoriten", favs)
+    if (favs.isNotEmpty()) groups += ModelGroup(favoritesLabel, favs)
 
     // Group models, sorting group labels (Vertex first, then OpenRouter)
     filtered.groupBy { groupFor(it) }
@@ -112,13 +114,14 @@ fun ModelSheet(
     val accent = LocalKaizenAccent.current
     val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
     var query by remember { mutableStateOf("") }
-    val groups = remember(models, favorites, query) { buildGroups(models, favorites, query) }
+    val favLabel = stringResource(R.string.model_favorites_group)
+    val groups = remember(models, favorites, query) { buildGroups(models, favorites, query, favLabel) }
 
     ModalBottomSheet(onDismissRequest = onDismiss, sheetState = sheetState) {
         Column(Modifier.fillMaxWidth().padding(horizontal = 20.dp)) {
             // --- Title ---
             Text(
-                "Modell auswählen",
+                stringResource(R.string.model_sheet_title),
                 color = cs.onBackground,
                 fontSize = 18.sp,
                 fontWeight = FontWeight.Bold,
@@ -145,7 +148,7 @@ fun ModelSheet(
                 Box(Modifier.weight(1f)) {
                     if (query.isEmpty()) {
                         Text(
-                            "Modell suchen…",
+                            stringResource(R.string.model_search_placeholder),
                             color = cs.onSurfaceVariant.copy(alpha = 0.5f),
                             fontSize = 14.sp
                         )
@@ -165,7 +168,7 @@ fun ModelSheet(
                 if (query.isNotEmpty()) {
                     Icon(
                         Icons.Rounded.Close,
-                        contentDescription = "Löschen",
+                        contentDescription = stringResource(R.string.model_search_clear),
                         tint = cs.onSurfaceVariant.copy(alpha = 0.6f),
                         modifier = Modifier
                             .size(18.dp)
@@ -180,7 +183,7 @@ fun ModelSheet(
                 if (groups.isEmpty()) {
                     item {
                         Text(
-                            if (models.isEmpty()) "Verbindung wird hergestellt..." else "Keine Treffer",
+                            if (models.isEmpty()) stringResource(R.string.model_connecting) else stringResource(R.string.model_no_results),
                             color = cs.onSurfaceVariant,
                             fontSize = 14.sp,
                             modifier = Modifier.padding(vertical = 24.dp),
@@ -292,7 +295,7 @@ private fun ModelRow(
         ) {
             Icon(
                 imageVector = if (favorite) Icons.Rounded.Star else Icons.Rounded.StarBorder,
-                contentDescription = "Favorit",
+                contentDescription = stringResource(R.string.model_favorite),
                 tint = if (favorite) accent.primary else cs.onSurfaceVariant.copy(alpha = 0.35f),
                 modifier = Modifier.size(20.dp),
             )
@@ -302,7 +305,7 @@ private fun ModelRow(
             Spacer(Modifier.size(4.dp))
             Icon(
                 Icons.Rounded.Check,
-                contentDescription = "Ausgewählt",
+                contentDescription = stringResource(R.string.model_selected),
                 tint = accent.primary,
                 modifier = Modifier.size(20.dp)
             )

app/src/main/java/dev/kaizen/app/settings/SettingsScreen.kt

@@ -93,7 +93,7 @@ fun SettingsScreen(
                     modifier = Modifier.size(44.dp).clickable { onBack() },
                 ) {
                     Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-                        Icon(Icons.AutoMirrored.Rounded.ArrowBack, "Zurück", tint = cs.onBackground, modifier = Modifier.size(20.dp))
+                        Icon(Icons.AutoMirrored.Rounded.ArrowBack, stringResource(R.string.settings_back), tint = cs.onBackground, modifier = Modifier.size(20.dp))
                     }
                 }