feat(update): notify about app updates on launch (chat banner) (#891)

Fires one silent update check per installed version at app start
(UpdateNoticeManager, release builds only) and shows a non-blocking
banner on the chat screen when a newer release exists. The About tab
adopts the launch result instead of re-pinging GitHub; dismissals
return on the next launch via the persisted latest tag.

Closes #890

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

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

@@ -77,8 +77,12 @@ import androidx.lifecycle.viewmodel.compose.viewModel
 import com.m57.hermescontrol.HistoryScreen
 import com.m57.hermescontrol.NavigationController
 import com.m57.hermescontrol.R
+import com.m57.hermescontrol.SettingsAbout
 import com.m57.hermescontrol.data.model.Attachment
 import com.m57.hermescontrol.data.model.AttachmentSource
+import com.m57.hermescontrol.data.update.AppUpdateCache
+import com.m57.hermescontrol.data.update.AppUpdateState
+import com.m57.hermescontrol.data.update.UpdateNoticeManager
 import com.m57.hermescontrol.data.ws.ConnectionStatus
 import com.m57.hermescontrol.data.ws.HermesWsClient
 import com.m57.hermescontrol.theme.LocalHermesStatusColors
@@ -102,6 +106,7 @@ import com.m57.hermescontrol.ui.common.AutoScrollingTitleText
 import com.m57.hermescontrol.ui.common.CredentialWarningBanner
 import com.m57.hermescontrol.ui.common.HermesScaffold
 import com.m57.hermescontrol.ui.common.NavIcon
+import com.m57.hermescontrol.ui.common.UpdateNoticeBanner
 import com.m57.hermescontrol.ui.model.components.ModelPickerDialog
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
@@ -518,6 +523,25 @@ fun ChatScreen(
                 )
             }
 
+            // Issue #890: launch update check — non-blocking banner when a
+            // newer release exists. "Update" jumps to the About-tab install
+            // flow; "Later" dismisses for the session (it returns next launch
+            // via the persisted latest tag). Release-only builds
+            // (UpdateNoticeManager.enabled = !BuildConfig.DEBUG).
+            val updateNotice by AppUpdateCache.state.collectAsStateWithLifecycle()
+            if (UpdateNoticeManager.enabled && !AppUpdateCache.dismissed) {
+                val noticeTag =
+                    (updateNotice as? AppUpdateState.UpdateAvailable)?.latestTag
+                        ?: UpdateNoticeManager.noticeTag()
+                if (noticeTag != null) {
+                    UpdateNoticeBanner(
+                        latestTag = noticeTag,
+                        onUpdate = { NavigationController.navigateTo(SettingsAbout) },
+                        onDismiss = { AppUpdateCache.dismiss() },
+                    )
+                }
+            }
+
             AnimatedVisibility(
                 visible = searchState.isActive,
                 enter = expandVertically() + fadeIn(),

app/src/main/java/com/m57/hermescontrol/ui/common/UpdateNoticeBanner.kt

@@ -0,0 +1,64 @@
+package com.m57.hermescontrol.ui.common
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Update
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.m57.hermescontrol.R
+
+/**
+ * Chat-screen banner for the launch update check (issue #890): a newer
+ * Hermes Mobile release exists. "Update" jumps into the About-tab install
+ * flow; "Later" dismisses for the session (the banner returns next launch).
+ */
+@Composable
+fun UpdateNoticeBanner(
+    latestTag: String,
+    onUpdate: () -> Unit,
+    onDismiss: () -> Unit,
+) {
+    Row(
+        modifier =
+            Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 12.dp, vertical = 6.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Icon(
+            imageVector = Icons.Filled.Update,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.primary,
+            modifier = Modifier.padding(top = 2.dp),
+        )
+        Text(
+            text = stringResource(R.string.update_notice_banner_text, latestTag),
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.weight(1f),
+        )
+        TextButton(onClick = onUpdate) {
+            Text(
+                text = stringResource(R.string.update_notice_banner_action),
+                style = MaterialTheme.typography.labelSmall,
+            )
+        }
+        TextButton(onClick = onDismiss) {
+            Text(
+                text = stringResource(R.string.action_dismiss),
+                style = MaterialTheme.typography.labelSmall,
+            )
+        }
+    }
+}

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

@@ -8,8 +8,11 @@ import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
 import com.m57.hermescontrol.BuildConfig
 import com.m57.hermescontrol.data.local.AuthManager
+import com.m57.hermescontrol.data.update.AppUpdateCache
 import com.m57.hermescontrol.data.update.AppUpdateChecker
+import com.m57.hermescontrol.data.update.AppUpdateState
 import com.m57.hermescontrol.data.update.isNewerVersion
+import com.m57.hermescontrol.data.update.releaseTag
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -19,36 +22,6 @@ import kotlinx.coroutines.launch
 import java.io.File
 import java.io.IOException
 
-/** UI state of the About-tab in-app updater (issue #867). */
-sealed interface AppUpdateState {
-    /** Nothing shown yet (no check run in this session). */
-    data object Idle : AppUpdateState
-
-    /** A check is in flight. */
-    data object Checking : AppUpdateState
-
-    /** Latest release equals the installed version. */
-    data class UpToDate(val latestTag: String) : AppUpdateState
-
-    /** A newer release with an APK asset exists. */
-    data class UpdateAvailable(
-        val latestTag: String,
-        val apkUrl: String,
-        val sizeBytes: Long,
-    ) : AppUpdateState
-
-    /** APK download in progress; [progress] is 0..1. */
-    data class Downloading(val progress: Float) : AppUpdateState
-
-    /** Download finished and the system package installer was launched. */
-    data class Installing(val latestTag: String) : AppUpdateState
-
-    /** Install-from-unknown-sources not granted for this app yet. */
-    data object NeedsUnknownSourcesPermission : AppUpdateState
-
-    data class Error(val message: String) : AppUpdateState
-}
-
 /**
  * Drives the in-app self-update flow (issue #867): check the GitHub
  * releases API, download the release APK, and hand it to the system package
@@ -76,6 +49,14 @@ class AppUpdateViewModel(
         // on every visit.
         if (AuthManager.getUpdateCheckDoneForVersion() != currentVersion) {
             checkForUpdate()
+        } else {
+            // Issue #890: the launch check (UpdateNoticeManager) already ran
+            // for this version — adopt its result instead of pinging GitHub
+            // again, so the About tab agrees with the chat banner.
+            val cached = AppUpdateCache.state.value
+            if (cached is AppUpdateState.UpdateAvailable || cached is AppUpdateState.UpToDate) {
+                _state.value = cached
+            }
         }
     }
 
@@ -115,6 +96,9 @@ class AppUpdateViewModel(
                 } else {
                     AppUpdateState.UpToDate(latestTag = info.tagName)
                 }
+            // Keep the launch notice (issue #890) in sync with manual checks.
+            AppUpdateCache.update(_state.value)
+            _state.value.releaseTag()?.let { AuthManager.setLastKnownLatestTag(it) }
         }
     }
 

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

@@ -21,7 +21,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import com.m57.hermescontrol.BuildConfig
 import com.m57.hermescontrol.R
-import com.m57.hermescontrol.ui.settings.AppUpdateState
+import com.m57.hermescontrol.data.update.AppUpdateState
 import com.m57.hermescontrol.ui.settings.InfoRow
 import com.m57.hermescontrol.ui.settings.SectionCard