feat(companion): kiosk session survives remote ⇄ dashboard navigation

The WEB_VIEW route recreated the WebView on every return from the
remote screen — full reload + re-login every time. The kiosk WebView is
now retained in a holder and reattached live (no race, no reload);
clients/bridges/listeners are re-bound to the new composition on
reattach, and the instance is dropped on retry, disconnect, or server
change so errored/stale sessions still reload for real.

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

Android/app/src/main/java/com/archipelago/app/ui/screens/WebViewScreen.kt

@@ -123,6 +123,23 @@ private fun isSameHost(url: String, base: String): Boolean {
     }
 }
 
+/** Kiosk WebView retained across navigation (remote ⇄ dashboard) so leaving
+ *  the kiosk and coming back reattaches the LIVE page — no reload, no
+ *  re-login, no reconnect. Dropped on retry/disconnect/server change. */
+private object KioskWebView {
+    var instance: WebView? = null
+    var url: String? = null
+
+    fun drop() {
+        instance?.let {
+            (it.parent as? ViewGroup)?.removeView(it)
+            it.destroy()
+        }
+        instance = null
+        url = null
+    }
+}
+
 /** True when a TCP listener answers at [base]'s host:port within [timeoutMs]. */
 private fun tcpAnswers(base: String, timeoutMs: Int): Boolean = try {
     val u = android.net.Uri.parse(base)
@@ -213,6 +230,13 @@ fun WebViewScreen(
     var startUrl by remember(serverUrl) { mutableStateOf<String?>(null) }
     var raceNonce by remember { mutableIntStateOf(0) }
     LaunchedEffect(serverUrl, meshFallbackUrl, raceNonce) {
+        // A retained live session exists — reattach instantly: no race, no
+        // reload, no re-login (remote ⇄ dashboard round trip).
+        if (KioskWebView.instance != null && KioskWebView.url == serverUrl) {
+            isLoading = false
+            startUrl = serverUrl
+            return@LaunchedEffect
+        }
         val picked = pickStartUrl(serverUrl, meshFallbackUrl)
         // Starting on the mesh: don't bounce back to it on error (it IS it).
         if (picked != serverUrl) triedMeshFallback = true
@@ -328,7 +352,10 @@ fun WebViewScreen(
                     text = stringResource(R.string.retry),
                     onClick = {
                         // Re-race LAN vs mesh — the network we're on may have
-                        // changed since the last pick.
+                        // changed since the last pick. Drop the retained view:
+                        // an errored session must genuinely reload.
+                        KioskWebView.drop()
+                        webView = null
                         hasError = false
                         isLoading = true
                         triedMeshFallback = false
@@ -342,7 +369,10 @@ fun WebViewScreen(
 
                 GlassButton(
                     text = stringResource(R.string.disconnect),
-                    onClick = onDisconnect,
+                    onClick = {
+                        KioskWebView.drop()
+                        onDisconnect()
+                    },
                     modifier = Modifier.fillMaxWidth().height(48.dp),
                 )
             }
@@ -359,7 +389,15 @@ fun WebViewScreen(
             AndroidView(
                 modifier = Modifier.fillMaxSize(),
                 factory = { context ->
-                    WebView(context).apply {
+                    // Reattach the retained kiosk WebView (remote ⇄ dashboard
+                    // must not reload the node UI). Everything configured
+                    // below is idempotent, and re-running it rebinds clients,
+                    // bridges and listeners to THIS composition's state —
+                    // stale closures from the previous visit are replaced.
+                    if (KioskWebView.url != serverUrl) KioskWebView.drop()
+                    val reused = KioskWebView.instance
+                    (reused ?: WebView(context)).apply {
+                        (parent as? ViewGroup)?.removeView(this)
                         layoutParams = ViewGroup.LayoutParams(
                             ViewGroup.LayoutParams.MATCH_PARENT,
                             ViewGroup.LayoutParams.MATCH_PARENT,
@@ -665,7 +703,11 @@ fun WebViewScreen(
                         }
 
                         webView = this
-                        loadUrl(initialUrl)
+                        if (reused == null) {
+                            KioskWebView.instance = this
+                            KioskWebView.url = serverUrl
+                            loadUrl(initialUrl)
+                        }
                     }
                 },
             )