app: make the Shizuku banner actionable (open Shizuku / request permission)

A third-party app cannot start Shizuku — the wireless-debugging pairing
flow is privileged and lives in Shizuku's own app — so the banner
deep-links there when it is installed but stopped, and fires the
permission request directly when it is running but unauthorised. The hint
line says which.

Verified on-device together with the earlier UX work: progress bar showing
"test 4 of 8 · icmp.ping6 · ~33s left", Cancel beside the disabled Run
button, cutout-safe title, and the banner live-updating from
not-running to needs-permission via the binder listener.

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

echolot-app/core-shizuku/src/main/kotlin/app/echo_lot/shizuku/ShizukuAvailability.kt

@@ -58,6 +58,28 @@ object ShizukuAvailability {
         State.NOT_INSTALLED -> null
     }
 
+    /**
+     * Intent that opens the Shizuku manager, where the user starts the service ("Start with
+     * wireless debugging" / root). A third-party app cannot start Shizuku itself — the pairing
+     * flow lives inside that app — so the best we can do is take the user straight there.
+     * Null when Shizuku isn't installed or exposes no launcher activity.
+     */
+    fun launchIntent(context: Context): android.content.Intent? =
+        context.packageManager.getLaunchIntentForPackage(SHIZUKU_PACKAGE)
+            ?.addFlags(android.content.Intent.FLAG_ACTIVITY_NEW_TASK)
+
+    /** Asks Shizuku for permission (only meaningful while it is running). */
+    fun requestPermission(requestCode: Int = 0xE1) {
+        runCatching { Shizuku.requestPermission(requestCode) }
+    }
+
+    /** What tapping the notice should do, so the UI can label it honestly. */
+    fun actionHint(s: State): String? = when (s) {
+        State.INSTALLED_NOT_RUNNING -> "Tap to open Shizuku and start it"
+        State.NEEDS_PERMISSION -> "Tap to grant permission"
+        else -> null
+    }
+
     /**
      * Reports the state now and on every binder transition. Returns a function that removes the
      * listeners again (call it from onCleared).