perf(#281): fix PERF-13/14/15/16 — main-thread settings, 100Hz polling, leaked scope, WS disconnect (#359)

* perf(#281): fix PERF-13/14/15/16 — main-thread settings load, 100Hz polling, leaked scope, WS disconnect

* fix(#281): fix SettingsViewModelTest failures from async init dispatcher

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatScreen.kt

@@ -797,10 +797,11 @@ private fun StreamingBubbleWithTypingEffect(
 
     // Timer that ticks at the configured delay, incrementing the visible word
     // count each tick. Stops ticking when streaming ends, then shows all words.
+    // Optimized: split is only called when waiting for new content, not per tick.
     LaunchedEffect(Unit) {
+        var wordCount = 0
         while (true) {
-            val words = currentContent.value.split(" ")
-            if (visibleWordCount < words.size) {
+            if (visibleWordCount < wordCount) {
                 delay(currentDelayMs.value.toLong())
                 visibleWordCount++
             } else {
@@ -808,7 +809,11 @@ private fun StreamingBubbleWithTypingEffect(
                     onAnimationComplete()
                     break
                 }
-                delay(10)
+                // Only split when we need to check for new content arriving
+                val words = currentContent.value.split(" ")
+                wordCount = words.size
+                if (visibleWordCount < wordCount) continue
+                delay(100) // was 10 — reduced from 100Hz to 10Hz
             }
         }
         visibleWordCount = Int.MAX_VALUE

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatViewModel.kt

@@ -1020,7 +1020,8 @@ class ChatViewModel(
     override fun onCleared() {
         super.onCleared()
         pendingCleanupJob?.cancel()
-        wsClient.disconnect()
+        // PERF-16: Don't disconnect the global HermesWsClient singleton when
+        // leaving the Chat screen — it's used by background notification reply.
     }
 
     companion object {

app/src/main/java/com/m57/hermescontrol/ui/settings/SettingsViewModel.kt

@@ -10,6 +10,7 @@ import com.m57.hermescontrol.data.remote.safeApiCall
 import com.m57.hermescontrol.theme.BottomNavDisplayMode
 import com.m57.hermescontrol.theme.ThemePreference
 import com.m57.hermescontrol.theme.ThemePreset
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -38,47 +39,57 @@ data class SettingsUiState(
     val bottomNavDisplayMode: BottomNavDisplayMode = BottomNavDisplayMode.ICON_AND_TEXT,
 )
 
-class SettingsViewModel : ViewModel() {
+class SettingsViewModel(
+    private val ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
+) : ViewModel() {
     private val _uiState = MutableStateFlow(SettingsUiState())
     val uiState: StateFlow<SettingsUiState> = _uiState.asStateFlow()
 
     init {
-        loadSettings()
+        viewModelScope.launch(ioDispatcher) {
+            loadSettings()
+        }
     }
 
-    private fun loadSettings() {
+    private suspend fun loadSettings() {
         val selectedId = AuthManager.getSelectedProfileId()
+        val host = AuthManager.getHost()
+        val port = AuthManager.getPort().toString()
+        val token = AuthManager.getToken() ?: ""
+        val autoReconnect = AuthManager.isAutoReconnect()
+        val themePreference = AuthManager.getThemePreference()
+        val useDynamicColors = AuthManager.isUseDynamicColors()
+        val themePreset = AuthManager.getThemePreset()
+        val selectedNavItems = AuthManager.getBottomNavItems()
+        val typingEffectEnabled = AuthManager.isTypingEffectEnabled()
+        val typingEffectDelayMs = AuthManager.getTypingEffectDelayMs()
+        val profiles = AuthManager.getConnectionProfiles()
+        val bottomNavDisplayMode = AuthManager.getBottomNavDisplayMode()
+        val renameProfileName =
+            profiles.firstOrNull { p -> p.id == selectedId }?.name ?: ""
         _uiState.update {
             it.copy(
-                host = AuthManager.getHost(),
-                port = AuthManager.getPort().toString(),
-                token = AuthManager.getToken() ?: "",
-                autoReconnect = AuthManager.isAutoReconnect(),
-                // B6 (Jun 18 2026, kanban t_86e9be9b): restore user's theme
-                // choice from persistent storage on init. Previously this slot
-                // was missing — always defaulted to ThemePreference.SYSTEM.
-                themePreference = AuthManager.getThemePreference(),
-                useDynamicColors = AuthManager.isUseDynamicColors(),
-                themePreset = AuthManager.getThemePreset(),
-                selectedNavItems = AuthManager.getBottomNavItems(),
-                typingEffectEnabled = AuthManager.isTypingEffectEnabled(),
-                typingEffectDelayMs = AuthManager.getTypingEffectDelayMs(),
-                profiles = AuthManager.getConnectionProfiles(),
+                host = host,
+                port = port,
+                token = token,
+                autoReconnect = autoReconnect,
+                themePreference = themePreference,
+                useDynamicColors = useDynamicColors,
+                themePreset = themePreset,
+                selectedNavItems = selectedNavItems,
+                typingEffectEnabled = typingEffectEnabled,
+                typingEffectDelayMs = typingEffectDelayMs,
+                profiles = profiles,
                 selectedProfileId = selectedId,
-                renameProfileName =
-                    AuthManager
-                        .getConnectionProfiles()
-                        .firstOrNull { p ->
-                            p.id == selectedId
-                        }?.name ?: "",
-                bottomNavDisplayMode = AuthManager.getBottomNavDisplayMode(),
+                renameProfileName = renameProfileName,
+                bottomNavDisplayMode = bottomNavDisplayMode,
             )
         }
     }
 
     fun selectProfile(profileId: String?) {
         AuthManager.setSelectedProfileId(profileId)
-        loadSettings()
+        viewModelScope.launch(ioDispatcher) { loadSettings() }
         ApiClient.rebuild()
     }
 
@@ -95,7 +106,7 @@ class SettingsViewModel : ViewModel() {
                 if (it.id == currentId) it.copy(name = newName) else it
             }
         AuthManager.saveConnectionProfiles(updatedProfiles)
-        loadSettings()
+        viewModelScope.launch(ioDispatcher) { loadSettings() }
     }
 
     fun deleteProfile(profileId: String) {
@@ -105,7 +116,7 @@ class SettingsViewModel : ViewModel() {
         if (AuthManager.getSelectedProfileId() == profileId) {
             AuthManager.setSelectedProfileId(null)
         }
-        loadSettings()
+        viewModelScope.launch(ioDispatcher) { loadSettings() }
         ApiClient.rebuild()
     }
 
@@ -207,8 +218,10 @@ class SettingsViewModel : ViewModel() {
         AuthManager.setTypingEffectDelayMs(state.typingEffectDelayMs)
         ApiClient.rebuild()
 
-        loadSettings()
-        _uiState.update { it.copy(isSaved = true, testResult = null) }
+        viewModelScope.launch(ioDispatcher) {
+            loadSettings()
+            _uiState.update { it.copy(isSaved = true, testResult = null) }
+        }
     }
 
     fun testConnection() {
@@ -225,7 +238,7 @@ class SettingsViewModel : ViewModel() {
 
         viewModelScope.launch {
             val result =
-                withContext(Dispatchers.IO) {
+                withContext(ioDispatcher) {
                     safeApiCall { ApiClient.hermesApi.getStatus() }
                 }
             when (result) {