fix(#425): live log updates + auto-scroll (#428)

* fix(#425): log screen doesn't auto-scroll on initial load

Replace animateScrollToItem(filteredLogs.size) with
scrollToItem(Int.MAX_VALUE). animateScrollToItem requires the
LazyColumn to have completed layout before it can calculate
animation targets — on initial load the list hasn't laid out
yet, so the scroll silently fails. scrollToItem is instant and
clamps Int.MAX_VALUE to the last item, working reliably even
on first composition.

* feat(#425): add auto-refresh polling for live log updates

LogsViewModel: add @Volatile loadInProgress guard to prevent
concurrent loads, and startAutoRefresh()/stopAutoRefresh() that
polls GET /api/logs every 5 seconds via viewModelScope coroutine.

LogsScreen: wire up DisposableEffect(Unit) to start polling when
the screen is composed and stop when disposed — so polling only
runs while the user is viewing the log screen.

Combined with scrollToItem(Int.MAX_VALUE) from previous commit,
logs now both auto-refresh AND auto-scroll to the latest entry.

* fix(#425): add missing viewModelScope import for CI build

LogsViewModel used viewModelScope directly in startAutoRefresh()
but never imported it — the original code only used it indirectly
via safeLaunchLoad which has its own import in ViewModelExt.kt.

---------

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

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

@@ -32,6 +32,7 @@ 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
@@ -125,12 +126,18 @@ fun LogsScreen(
         viewModel.loadLogs()
     }
 
+    // Auto-refresh logs via polling while the screen is visible
+    DisposableEffect(Unit) {
+        viewModel.startAutoRefresh()
+        onDispose { viewModel.stopAutoRefresh() }
+    }
+
     ToastEffect(toastMessage = state.toastMessage, onClearToast = viewModel::clearToast)
 
     // Auto-scroll to bottom when new logs arrive (unless paused)
     LaunchedEffect(filteredLogs.size, pauseScroll) {
         if (!pauseScroll && filteredLogs.isNotEmpty()) {
-            listState.animateScrollToItem(filteredLogs.size)
+            listState.scrollToItem(Int.MAX_VALUE)
         }
     }
 

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

@@ -1,14 +1,19 @@
 package com.m57.hermescontrol.ui.logs
 
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
 import com.m57.hermescontrol.data.remote.ApiClient
 import com.m57.hermescontrol.data.remote.safeApiCall
 import com.m57.hermescontrol.ui.common.ToastHost
 import com.m57.hermescontrol.ui.common.safeLaunchLoad
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
 
 data class LogsUiState(
     val isLoading: Boolean = false,
@@ -21,7 +26,14 @@ class LogsViewModel : ViewModel(), ToastHost {
     private val _uiState = MutableStateFlow(LogsUiState())
     val uiState: StateFlow<LogsUiState> = _uiState.asStateFlow()
 
+    @Volatile
+    private var loadInProgress = false
+
+    private var autoRefreshJob: Job? = null
+
     fun loadLogs() {
+        if (loadInProgress) return
+        loadInProgress = true
         safeLaunchLoad(
             apiCall = { safeApiCall { ApiClient.hermesApi.getLogs(lines = 1000) } },
             onStart = { _uiState.update { it.copy(isLoading = true, errorMessage = null) } },
@@ -29,6 +41,7 @@ class LogsViewModel : ViewModel(), ToastHost {
                 val body = data
                 val logsList = body.lines ?: body.logs ?: emptyList()
                 _uiState.update { it.copy(isLoading = false, logs = logsList) }
+                loadInProgress = false
             },
             onError = { errorMsg ->
                 _uiState.update {
@@ -37,10 +50,29 @@ class LogsViewModel : ViewModel(), ToastHost {
                         errorMessage = "Failed to load logs: $errorMsg",
                     )
                 }
+                loadInProgress = false
             },
         )
     }
 
+    /** Start auto-refreshing logs every 5 seconds. */
+    fun startAutoRefresh() {
+        if (autoRefreshJob?.isActive == true) return
+        autoRefreshJob =
+            viewModelScope.launch {
+                while (isActive) {
+                    delay(5_000)
+                    loadLogs()
+                }
+            }
+    }
+
+    /** Stop auto-refreshing logs. */
+    fun stopAutoRefresh() {
+        autoRefreshJob?.cancel()
+        autoRefreshJob = null
+    }
+
     override fun clearToast() {
         _uiState.update { it.copy(toastMessage = null) }
     }