app: tell the user before the run when Shizuku is installed but not started

Distinguishes not-installed (say nothing — don't nag users who don't use
Shizuku) from installed-but-stopped (amber banner: start it to include
shell-tier tests), plus running-unauthorised and ready. Detection is
listener-based since pingBinder() only becomes truthful once
ShizukuProvider delivers the binder; a launch-time poll would show a false
"not running". Installed-vs-not needs the <queries> entry on Android 11+.

Verified on-device: with shizuku_server stopped, the banner shows before
pressing Run; the title also now clears the status bar/cutout after the
safeDrawingPadding fix.

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

echolot-app/app/src/main/kotlin/app/echo_lot/app/MainActivity.kt

@@ -115,6 +115,22 @@ private fun EcholotScreen(
         Text("Echolot", fontSize = 26.sp, fontWeight = FontWeight.SemiBold)
         Text("measure, don't guess", color = MaterialTheme.colorScheme.onSurfaceVariant, fontSize = 13.sp)
 
+        // Shell-tier readiness, before the run. Nothing is shown when Shizuku isn't installed —
+        // only users who actually use it get reminded that it must be running.
+        state.shizukuNotice?.let { notice ->
+            Card(
+                Modifier.fillMaxWidth(),
+                colors = CardDefaults.cardColors(
+                    containerColor = if (state.shizukuReady) Color(0xFF14301F) else Color(0xFF3A2E12),
+                ),
+            ) {
+                Text(
+                    notice, Modifier.padding(10.dp), fontSize = 12.sp,
+                    color = if (state.shizukuReady) Color(0xFF9CCFA8) else Color(0xFFFFD08A),
+                )
+            }
+        }
+
         Row(horizontalArrangement = Arrangement.spacedBy(12.dp), verticalAlignment = Alignment.CenterVertically) {
             Button(onClick = onRun, enabled = !state.running) {
                 Text(if (state.running) "Running…" else "Run measurement")

echolot-app/app/src/main/kotlin/app/echo_lot/app/RunViewModel.kt

@@ -20,6 +20,7 @@ import app.echo_lot.probe.NetworkInventory
 import app.echo_lot.probe.Probe
 import app.echo_lot.probe.ProbeIds
 import app.echo_lot.probe.RouterIdentityProbe
+import app.echo_lot.shizuku.ShizukuAvailability
 import app.echo_lot.shizuku.ShizukuProbe
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -37,6 +38,9 @@ data class UiState(
     val stepsDone: Int = 0,
     val stepsTotal: Int = 0,
     val etaSeconds: Int = 0,
+    /** Shell-tier readiness, shown before a run; null message = say nothing (Shizuku not installed). */
+    val shizukuNotice: String? = null,
+    val shizukuReady: Boolean = false,
 )
 
 /**
@@ -51,6 +55,24 @@ class RunViewModel(app: Application) : AndroidViewModel(app) {
         private set
 
     private var runJob: kotlinx.coroutines.Job? = null
+    private val stopShizukuObserver: () -> Unit
+
+    init {
+        // Report shell-tier readiness up front. The binder arrives asynchronously, so this is a
+        // listener, not a one-shot poll — otherwise a running Shizuku would look "not running"
+        // for the first moment after launch.
+        stopShizukuObserver = ShizukuAvailability.observe(app) { st ->
+            state = state.copy(
+                shizukuNotice = ShizukuAvailability.describe(st),
+                shizukuReady = st == ShizukuAvailability.State.READY,
+            )
+        }
+    }
+
+    override fun onCleared() {
+        stopShizukuObserver()
+        super.onCleared()
+    }
     // Results collected so far. A cancelled run must still be able to show what it measured.
     private val collected = mutableListOf<Test>()
     private var runIds: RunIds = RunIds()