Make a waiting update visible instead of hiding it in the settings

The start-up check already ran, but its result only showed as a badge for
whoever happened to open the settings. A chip in the top bar now says
"Update <version>" and leads straight there, and the check repeats every
six hours because a TV keeps the same process alive for days.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/src/main/java/dev/castarr/tv/MainActivity.kt

@@ -50,7 +50,14 @@ class MainActivity : ComponentActivity(), ControlServer.Listener {
         server.startServer()
         state.remoteAvailable = server.running
         setContent { CastarrApp(state) }
-        lifecycleScope.launch { UpdateChecker.check(state) }
+        lifecycleScope.launch {
+            // At start-up and then occasionally: a TV often keeps the same
+            // app process alive for days.
+            while (true) {
+                UpdateChecker.check(state)
+                delay(UPDATE_CHECK_INTERVAL_MS)
+            }
+        }
     }
 
     private fun onPlaybackChanged() {
@@ -325,5 +332,6 @@ class MainActivity : ComponentActivity(), ControlServer.Listener {
         const val TICK_INTERVAL_MS = 2_000L
         const val SEEK_STEP_SECONDS = 10L
         const val DIGIT_COMMIT_MS = 1_800L
+        const val UPDATE_CHECK_INTERVAL_MS = 6 * 60 * 60 * 1000L
     }
 }

app/src/main/java/dev/castarr/tv/ui/CastarrApp.kt

@@ -132,6 +132,10 @@ private fun TopBar(state: AppState) {
             }
             Spacer(Modifier.width(18.dp))
         }
+        state.updateAvailable?.let { version ->
+            UpdateChip(version) { state.screen = AppState.Screen.SETTINGS }
+            Spacer(Modifier.width(10.dp))
+        }
         GearButton {
             state.screen = if (state.screen == AppState.Screen.LIVE) AppState.Screen.SETTINGS
             else AppState.Screen.LIVE
@@ -139,6 +143,33 @@ private fun TopBar(state: AppState) {
     }
 }
 
+/**
+ * Shown in the top bar as soon as the start-up check finds a newer
+ * release — otherwise an update would only be noticed by someone who
+ * happens to open the settings.
+ */
+@Composable
+private fun UpdateChip(version: String, onClick: () -> Unit) {
+    Surface(
+        onClick = onClick,
+        shape = ClickableSurfaceDefaults.shape(RoundedCornerShape(999.dp)),
+        colors = ClickableSurfaceDefaults.colors(
+            containerColor = CastarrColors.accentDim,
+            contentColor = CastarrColors.accent,
+            focusedContainerColor = CastarrColors.accent,
+            focusedContentColor = CastarrColors.onAccent,
+        ),
+    ) {
+        Text(
+            "Update $version",
+            fontFamily = AppFont,
+            fontSize = 13.sp,
+            fontWeight = FontWeight.Medium,
+            modifier = Modifier.padding(horizontal = 14.dp, vertical = 8.dp),
+        )
+    }
+}
+
 /** Round settings button with a drawn gear (glyphs render as emoji). */
 @Composable
 private fun GearButton(onClick: () -> Unit) {