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/system/SystemScreen.kt

@@ -1,5 +1,6 @@
 package com.m57.hermescontrol.ui.system
 
+import android.app.Application
 import android.net.Uri
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
@@ -125,8 +126,10 @@ private fun formatDuration(totalSeconds: Double): String {
 fun SystemScreen(
     modifier: Modifier = Modifier,
     onOpenDrawer: (() -> Unit)? = null,
-    viewModel: SystemViewModel = viewModel { SystemViewModel() },
+    viewModel: SystemViewModel? = null,
 ) {
+    val app = LocalContext.current.applicationContext as Application
+    val viewModel = viewModel ?: viewModel { SystemViewModel(app) }
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     val spacing = LocalSpacing.current
     val statusColors = LocalHermesStatusColors.current
@@ -854,7 +857,7 @@ private fun LazyListScope.gatewaySection(
                     // Auth required
                     status.auth_required?.let { auth ->
                         InfoRow(
-                            label = "Auth required",
+                            label = stringResource(R.string.system_auth_required),
                             value = if (auth) "yes" else "no",
                         )
                     }
@@ -1670,7 +1673,7 @@ private fun LazyListScope.actionLogSection(
                                 }
                                 if (lines.size > 20) {
                                     Text(
-                                        text = "... ${lines.size - 20} more line(s)",
+                                        text = stringResource(R.string.system_more_lines, lines.size - 20),
                                         style = MaterialTheme.typography.bodySmall,
                                         color = MaterialTheme.colorScheme.onSurfaceVariant,
                                     )

app/src/main/java/com/m57/hermescontrol/ui/system/SystemViewModel.kt

@@ -1,9 +1,12 @@
 package com.m57.hermescontrol.ui.system
 
+import android.app.Application
 import android.util.Log
-import androidx.lifecycle.ViewModel
+import androidx.annotation.StringRes
+import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
 import com.m57.hermescontrol.BuildConfig
+import com.m57.hermescontrol.R
 import com.m57.hermescontrol.data.model.ActionResponse
 import com.m57.hermescontrol.data.model.ActionStatusResponse
 import com.m57.hermescontrol.data.model.BackupTriggerRequest
@@ -83,8 +86,8 @@ data class SystemUiState(
     val updateConfirmOpen: Boolean = false,
 )
 
-class SystemViewModel :
-    ViewModel(),
+class SystemViewModel(application: Application) :
+    AndroidViewModel(application),
     ToastHost {
     companion object {
         private const val TAG = "SystemViewModel"
@@ -348,7 +351,7 @@ class SystemViewModel :
     fun runCuratorNow() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.runCurator() } },
-            label = "Curator run",
+            labelRes = R.string.system_curator_run,
         )
     }
 
@@ -433,35 +436,35 @@ class SystemViewModel :
     fun runSecurityAudit() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.runSecurityAudit() } },
-            label = "Security audit",
+            labelRes = R.string.system_security_audit,
         )
     }
 
     fun runPromptSize() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.runPromptSize() } },
-            label = "Prompt size check",
+            labelRes = R.string.system_prompt_size_check,
         )
     }
 
     fun runDump() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.runDump() } },
-            label = "Dump",
+            labelRes = R.string.system_dump,
         )
     }
 
     fun runConfigMigrate() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.runConfigMigrate() } },
-            label = "Config migrate",
+            labelRes = R.string.system_config_migrate,
         )
     }
 
     fun runUpdateSkills() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.updateSkillsFromHub() } },
-            label = "Skills update",
+            labelRes = R.string.system_skills_update,
         )
     }
 
@@ -654,7 +657,7 @@ class SystemViewModel :
     fun pruneCheckpoints() {
         runOperation(
             apiCall = { safeApiCall { ApiClient.hermesApi.pruneCheckpoints() } },
-            label = "Checkpoint prune",
+            labelRes = R.string.system_checkpoint_prune,
         )
     }
 
@@ -786,18 +789,35 @@ class SystemViewModel :
 
     private fun runOperation(
         apiCall: suspend () -> NetworkResult<ActionResponse>,
-        label: String,
+        @StringRes labelRes: Int,
     ) {
         viewModelScope.launch {
             val result = withContext(Dispatchers.IO) { apiCall() }
             when (result) {
                 is NetworkResult.Success -> {
                     result.data.name?.let { pollActionStatus(it) }
-                    _uiState.update { it.copy(toastMessage = "$label started") }
+                    _uiState.update {
+                        it.copy(
+                            toastMessage =
+                                getApplication<Application>().getString(
+                                    R.string.system_action_started,
+                                    getApplication<Application>().getString(labelRes),
+                                ),
+                        )
+                    }
                 }
 
                 is NetworkResult.Failure -> {
-                    _uiState.update { it.copy(toastMessage = "$label failed: ${result.error.message}") }
+                    _uiState.update {
+                        it.copy(
+                            toastMessage =
+                                getApplication<Application>().getString(
+                                    R.string.system_action_failed,
+                                    getApplication<Application>().getString(labelRes),
+                                    result.error.message,
+                                ),
+                        )
+                    }
                 }
             }
         }