Add Simplified Chinese (zh) localization (#901)

* feat: add Simplified Chinese (zh) localization

- Add complete values-zh/strings.xml (921 strings, all keys covered)
- Translate 107 hardcoded UI strings across 34 Kotlin files
- Add 简体中文 option to in-app language picker
- Terminology aligned with official Hermes dashboard zh translations

* fix: resource-ize hardcoded Chinese strings per review

Address Hy4ri's review on PR #901:
- Move 104 hardcoded Chinese UI strings to string resources
  (English in values/strings.xml, Chinese in values-zh/strings.xml)
  referenced via stringResource()
- SystemViewModel labels -> @StringRes + AndroidViewModel with
  resource-based toast templates
- Make TodoTaskCardTest assertion locale-agnostic via getString()
- Update cookie tests to assert new host-agnostic session cookie
  behavior (WiFi/Tailscale switch-safe)
- Session cookie mirroring to WILDCARD bucket survives host switches

* style: apply ktlintFormat per review

---------

Co-authored-by: hermes-i18n <hermes-i18n@localhost>

app/src/main/java/com/m57/hermescontrol/ui/model/ModelScreen.kt

@@ -157,7 +157,7 @@ fun ModelScreen(
                         SearchBar(
                             query = query,
                             onQueryChange = { query = it },
-                            placeholder = "Search models...",
+                            placeholder = stringResource(R.string.model_search_placeholder),
                         )
                     }
 
@@ -221,7 +221,7 @@ fun ModelScreen(
     if (state.modelPickerConfirmMessage != null) {
         AlertDialog(
             onDismissRequest = { viewModel.dismissModelPickerConfirm() },
-            title = { Text("Expensive Model") },
+            title = { Text(stringResource(R.string.model_expensive_title)) },
             text = { Text(state.modelPickerConfirmMessage!!) },
             confirmButton = {
                 Button(onClick = { viewModel.confirmModelPickerExpensive() }) {
@@ -240,7 +240,7 @@ fun ModelScreen(
     if (state.showMainModelPicker) {
         ModelPickerDialog(
             providers = state.providers,
-            title = "Set Main Model",
+            title = stringResource(R.string.model_set_main),
             isLoading = state.isLoading && state.providers.isEmpty(),
             pinnedModels = state.pinnedModels,
             onPinToggle = { provider, model -> viewModel.togglePinModel(provider, model) },
@@ -266,7 +266,7 @@ fun ModelScreen(
     if (state.showAuxModelPicker) {
         ModelPickerDialog(
             providers = state.providers,
-            title = "Set Aux: ${state.auxPickerTask}",
+            title = stringResource(R.string.model_set_aux, state.auxPickerTask),
             isLoading = state.isLoading && state.providers.isEmpty(),
             pinnedModels = state.pinnedModels,
             onPinToggle = { provider, model -> viewModel.togglePinModel(provider, model) },
@@ -330,12 +330,12 @@ private fun ModelSettingsSection(
                     modifier = Modifier.size(16.dp),
                 )
                 Text(
-                    text = "Model Settings",
+                    text = stringResource(R.string.model_settings),
                     style = MaterialTheme.typography.titleSmall,
                     fontWeight = FontWeight.Bold,
                 )
                 Text(
-                    text = "applies to new sessions",
+                    text = stringResource(R.string.model_new_sessions),
                     style = MaterialTheme.typography.bodySmall,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
@@ -353,7 +353,7 @@ private fun ModelSettingsSection(
                         modifier = Modifier.size(16.dp),
                     )
                 },
-                label = "Main model",
+                label = stringResource(R.string.model_main_label),
                 value = if (mainProvider.isNotBlank()) "$mainProvider · $mainModel" else "(unset)",
                 actionLabel = "Change",
                 onAction = onSetMainModel,
@@ -371,7 +371,7 @@ private fun ModelSettingsSection(
                         modifier = Modifier.size(16.dp),
                     )
                 },
-                label = "Auxiliary tasks",
+                label = stringResource(R.string.model_aux_tasks_label),
                 value =
                     if (auxOverrideCount > 0) {
                         "$auxOverrideCount override · ${AUX_TASKS.size - auxOverrideCount} auto"
@@ -394,7 +394,7 @@ private fun ModelSettingsSection(
                         modifier = Modifier.size(16.dp),
                     )
                 },
-                label = "Mixture of Agents",
+                label = stringResource(R.string.model_moa_label),
                 value = if (moaEnabled) moaSummary else "not loaded",
                 actionLabel = "Configure",
                 onAction = onConfigureMoa,
@@ -461,7 +461,7 @@ private fun AuxTasksDialog(
 ) {
     AlertDialog(
         onDismissRequest = onDismiss,
-        title = { Text("Auxiliary Tasks") },
+        title = { Text(stringResource(R.string.model_aux_tasks_title)) },
         text = {
             Column {
                 Text(
@@ -530,7 +530,7 @@ private fun AuxTasksDialog(
                 ) {
                     Icon(Icons.Filled.Delete, contentDescription = null, modifier = Modifier.size(14.dp))
                     Spacer(modifier = Modifier.width(4.dp))
-                    Text("Reset all to auto")
+                    Text(stringResource(R.string.model_reset_all_auto))
                 }
             }
         },

app/src/main/java/com/m57/hermescontrol/ui/model/components/MoaConfigDialog.kt

@@ -34,8 +34,10 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import com.m57.hermescontrol.R
 import com.m57.hermescontrol.data.model.MoaConfigPreset
 import com.m57.hermescontrol.data.model.MoaModelSlot
 import com.m57.hermescontrol.ui.common.SearchBar
@@ -58,7 +60,7 @@ internal fun MoaConfigDialog(
 
     AlertDialog(
         onDismissRequest = onDismiss,
-        title = { Text("Mixture of Agents") },
+        title = { Text(stringResource(R.string.moa_title)) },
         text = {
             if (pickerTarget != null && effectivePreset != null) {
                 // Inline model picker within the dialog
@@ -228,13 +230,13 @@ private fun MoaConfigEditor(
 ) {
     Column {
         Text(
-            text = "Presets appear as models under the Mixture of Agents provider.",
+            text = stringResource(R.string.moa_presets_note),
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
 
         if (effectivePreset == null) {
-            Text("No presets configured", style = MaterialTheme.typography.bodyMedium)
+            Text(stringResource(R.string.moa_no_presets), style = MaterialTheme.typography.bodyMedium)
             return
         }
 
@@ -248,7 +250,7 @@ private fun MoaConfigEditor(
         ) {
             // Simplified preset dropdown with buttons
             if (presetNames.isNotEmpty()) {
-                Text("Preset:", style = MaterialTheme.typography.bodySmall)
+                Text(stringResource(R.string.moa_preset_label), style = MaterialTheme.typography.bodySmall)
                 presetNames.forEach { name ->
                     TextButton(
                         onClick = { onSelectPreset(name) },
@@ -286,7 +288,7 @@ private fun MoaConfigEditor(
                 contentPadding = PaddingValues(horizontal = 8.dp, vertical = 4.dp),
                 enabled = presetNames.size > 1,
             ) {
-                Text("Set default", style = MaterialTheme.typography.labelSmall)
+                Text(stringResource(R.string.moa_set_default), style = MaterialTheme.typography.labelSmall)
             }
             OutlinedButton(
                 onClick = onDeletePreset,
@@ -306,13 +308,18 @@ private fun MoaConfigEditor(
             OutlinedTextField(
                 value = newPresetName,
                 onValueChange = onNewPresetNameChange,
-                placeholder = { Text("new preset name", style = MaterialTheme.typography.bodySmall) },
+                placeholder = {
+                    Text(
+                        stringResource(R.string.moa_new_preset_name),
+                        style = MaterialTheme.typography.bodySmall,
+                    )
+                },
                 singleLine = true,
                 modifier = Modifier.weight(1f).height(48.dp),
                 textStyle = MaterialTheme.typography.bodySmall,
             )
             IconButton(onClick = onAddPreset, enabled = newPresetName.isNotBlank()) {
-                Icon(Icons.Outlined.Add, contentDescription = "Add preset")
+                Icon(Icons.Outlined.Add, contentDescription = stringResource(R.string.moa_add_preset))
             }
         }
 
@@ -320,7 +327,7 @@ private fun MoaConfigEditor(
 
         // Reference models
         Text(
-            text = "Reference models",
+            text = stringResource(R.string.moa_reference_models),
             style = MaterialTheme.typography.bodySmall,
             fontWeight = FontWeight.Bold,
         )
@@ -355,7 +362,7 @@ private fun MoaConfigEditor(
         ) {
             Icon(Icons.Outlined.Add, contentDescription = null, modifier = Modifier.size(14.dp))
             Spacer(modifier = Modifier.width(4.dp))
-            Text("Add reference model", style = MaterialTheme.typography.labelSmall)
+            Text(stringResource(R.string.moa_add_reference), style = MaterialTheme.typography.labelSmall)
         }
 
         Spacer(modifier = Modifier.height(8.dp))
@@ -412,7 +419,7 @@ private fun MoaSlotPicker(
         SearchBar(
             query = pickerQuery,
             onQueryChange = { pickerQuery = it },
-            placeholder = "Search providers...",
+            placeholder = stringResource(R.string.moa_search_providers),
         )
         Spacer(modifier = Modifier.height(8.dp))
 

app/src/main/java/com/m57/hermescontrol/ui/model/components/ModelPickerDialog.kt

@@ -32,9 +32,11 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import com.m57.hermescontrol.R
 import com.m57.hermescontrol.data.model.ModelProvider
 import com.m57.hermescontrol.data.model.PinnedModel
 import com.m57.hermescontrol.ui.common.LoadingState
@@ -95,12 +97,12 @@ fun ModelPickerDialog(
             Column {
                 if (isLoading) {
                     LoadingState(
-                        subtitle = "Loading models…",
+                        subtitle = stringResource(R.string.model_picker_loading),
                         modifier = Modifier.fillMaxWidth(),
                     )
                 } else if (providers.isEmpty() && pinnedModels.isEmpty()) {
                     Text(
-                        text = "No models available.",
+                        text = stringResource(R.string.model_picker_no_models),
                         style = MaterialTheme.typography.bodyMedium,
                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                     )
@@ -143,7 +145,7 @@ fun ModelPickerDialog(
                     SearchBar(
                         query = pickerQuery,
                         onQueryChange = { pickerQuery = it },
-                        placeholder = "Search models and providers...",
+                        placeholder = stringResource(R.string.model_picker_search),
                     )
                     Spacer(modifier = Modifier.height(12.dp))