perf(ui): suspend polling outside visible screens (#806)

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

@@ -66,7 +66,10 @@ import androidx.compose.ui.text.input.TextFieldValue
 import androidx.compose.ui.unit.dp
 import androidx.core.content.ContextCompat
 import androidx.core.content.FileProvider
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.m57.hermescontrol.NavigationController
 import com.m57.hermescontrol.R
@@ -102,7 +105,7 @@ import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
 
-private const val SESSION_SYNC_INTERVAL_MS = 5_000L
+private const val SESSION_SYNC_INTERVAL_MS = 30_000L
 
 /**
  * Chat screen — the primary conversation surface of Hermes Control.
@@ -126,6 +129,7 @@ fun ChatScreen(
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     val streamingState by viewModel.streamingState.collectAsStateWithLifecycle()
     val credentialWarning by HermesWsClient.credentialWarning.collectAsStateWithLifecycle()
+    val lifecycleOwner = LocalLifecycleOwner.current
     val listState = rememberLazyListState()
     val scrollScope = rememberCoroutineScope()
     val scrollController = rememberChatScrollController(listState, scrollScope)
@@ -133,7 +137,8 @@ fun ChatScreen(
     var showContextSheet by remember { mutableStateOf(false) }
 
     // Periodic session sync while connected.
-    LaunchedEffect(state.currentSessionId, state.connectionStatus) {
+    LaunchedEffect(lifecycleOwner, state.currentSessionId, state.connectionStatus) {
+        lifecycleOwner.lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED) {
             if (state.currentSessionId != null && state.connectionStatus == ConnectionStatus.CONNECTED) {
                 viewModel.syncCurrentSession()
                 viewModel.fetchContextUsage()
@@ -144,6 +149,7 @@ fun ChatScreen(
                 viewModel.fetchContextUsage()
             }
         }
+    }
 
     // Arm + trigger older-message paging when the user scrolls near the top.
     // Before prepending, capture the anchor (first visible message id + offset)

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

@@ -2238,7 +2238,7 @@ class ChatViewModel(
      * Both calls are independent and best-effort: a failure on one must not
      * wipe the other's already-shown value, and neither blocks the chat. The
      * two fetches are launched separately so a slow/erroring one can't starve
-     * the other. Polled from [syncCurrentSession] via the 5s loop and re-fired
+     * the other. Polled from [syncCurrentSession] via the 30s loop and re-fired
      * on model switch (the denominator changes).
      */
     fun fetchContextUsage() {

app/src/main/java/com/m57/hermescontrol/ui/logs/LogsScreen.kt

@@ -31,7 +31,6 @@ import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -45,6 +44,7 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.lifecycle.compose.LifecycleStartEffect
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.m57.hermescontrol.R
@@ -120,9 +120,9 @@ fun LogsScreen(
     }
 
     // Auto-refresh logs via polling while the screen is visible
-    DisposableEffect(Unit) {
+    LifecycleStartEffect(viewModel) {
         viewModel.startAutoRefresh()
-        onDispose { viewModel.stopAutoRefresh() }
+        onStopOrDispose { viewModel.stopAutoRefresh() }
     }
 
     ToastEffect(toastMessage = state.toastMessage, onClearToast = viewModel::clearToast)