feat(companion): instant off-LAN startup + same-node apps stay in-app

Two field reports from tonight's 5G session:

- 'Stuck connecting': the kiosk WebView always loaded the LAN URL first,
  and Chromium burns a minute+ of connect retries on a dead LAN IP before
  the mesh fallback fires. WebViewScreen now races a raw TCP probe — LAN
  gets 2.5s, else the mesh ULA (patient, 12s) — BEFORE creating the
  WebView, so startup lands on the right origin in seconds either side.
  Retry re-races instead of blindly reloading the LAN URL.
- Pine/Home Assistant/BTCPay opened in the external browser over the
  mesh: same-node detection compared one host, but the node has two (LAN
  origin + mesh ULA) — kiosk loaded via the ULA meant app links failed
  isSameHost and routeOutbound bounced them to the browser. Same-node now
  matches either address, in the kiosk router, SSL allowances and the
  InAppBrowser.

Served APK: 0.5.6 (vc26). Note: the binary also carries the in-flight
listen_port groundwork from the dev-box session's archy-fips-core WIP
(compiles clean, default posture unchanged); its source lands separately.

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

Android/app/build.gradle.kts

@@ -11,8 +11,8 @@ android {
         applicationId = "com.archipelago.app"
         minSdk = 26
         targetSdk = 35
-        versionCode = 25
-        versionName = "0.5.5"
+        versionCode = 26
+        versionName = "0.5.6"
 
         vectorDrawables {
             useSupportLibrary = true

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

@@ -87,6 +87,28 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import org.json.JSONObject
 
+/** 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)
+    val port = if (u.port != -1) u.port else if (u.scheme == "https") 443 else 80
+    java.net.Socket().use {
+        it.connect(java.net.InetSocketAddress(u.host, port), timeoutMs)
+        true
+    }
+} catch (_: Exception) {
+    false
+}
+
+/** Fastest answering origin: LAN inside a short window, else the mesh ULA
+ *  (patient — a cold session may still be establishing), else LAN anyway so
+ *  the existing error/fallback path handles it. */
+private suspend fun pickStartUrl(lanUrl: String, meshUrl: String?): String =
+    withContext(Dispatchers.IO) {
+        if (tcpAnswers(lanUrl, 2500)) return@withContext lanUrl
+        if (meshUrl != null && tcpAnswers(meshUrl, 12_000)) return@withContext meshUrl
+        lanUrl
+    }
+
 /** Open a URL in the phone's default browser (genuinely external links). */
 private fun openExternalUrl(context: android.content.Context, url: String) {
     try {
@@ -168,6 +190,20 @@ fun WebViewScreen(
     var hasError by remember { mutableStateOf(false) }
     var webView by remember { mutableStateOf<WebView?>(null) }
 
+    // Race LAN vs mesh BEFORE the WebView exists: Chromium pointed at an
+    // unreachable LAN IP burns a minute+ in connect retries before
+    // onReceivedError fires the mesh fallback — the "stuck connecting"
+    // stall. A raw TCP probe answers in milliseconds at home and fails in
+    // ~2.5s off-LAN, so startup lands on the right origin in seconds.
+    var startUrl by remember(serverUrl) { mutableStateOf<String?>(null) }
+    var raceNonce by remember { mutableIntStateOf(0) }
+    LaunchedEffect(serverUrl, meshFallbackUrl, raceNonce) {
+        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
+        startUrl = picked
+    }
+
     // Web-page camera access (wallet QR scanner). The WebView's default
     // WebChromeClient silently denies getUserMedia, so grant video capture —
     // asking for the app-level CAMERA permission first when needed.
@@ -187,6 +223,14 @@ fun WebViewScreen(
     // while this is shown, so closing it returns instantly with no reload.
     var inAppUrl by remember { mutableStateOf<String?>(null) }
 
+    // Same node = EITHER of its addresses. Over the mesh the kiosk's host is
+    // the ULA while app links may carry the LAN IP (and vice versa) —
+    // comparing against one host bounced same-node apps (Pine, Home
+    // Assistant) out to the phone's external browser.
+    fun isSameNode(url: String): Boolean =
+        isSameHost(url, serverUrl) ||
+            (meshFallbackUrl != null && isSameHost(url, meshFallbackUrl))
+
     // Native wallet QR scanner, opened by the web UI via the ArchipelagoQr
     // bridge; status lines stream back from the page while it's up.
     var walletScannerVisible by remember { mutableStateOf(false) }
@@ -268,9 +312,13 @@ fun WebViewScreen(
                 GlassButton(
                     text = stringResource(R.string.retry),
                     onClick = {
+                        // Re-race LAN vs mesh — the network we're on may have
+                        // changed since the last pick.
                         hasError = false
                         isLoading = true
-                        webView?.loadUrl(serverUrl)
+                        triedMeshFallback = false
+                        startUrl = null
+                        raceNonce++
                     },
                     modifier = Modifier.fillMaxWidth().height(56.dp),
                 )
@@ -283,9 +331,16 @@ fun WebViewScreen(
                     modifier = Modifier.fillMaxWidth().height(48.dp),
                 )
             }
+        } else if (startUrl == null) {
+            // Racing LAN vs mesh (≤2.5s at home, a few seconds off-LAN) —
+            // far cheaper than letting Chromium retry a dead LAN IP.
+            Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                CircularProgressIndicator(color = BitcoinOrange)
+            }
         } else {
             // Edge-to-edge WebView — background bleeds behind status bar.
             // Safe area values injected as CSS env() polyfill on each page load.
+            val initialUrl = startUrl ?: serverUrl
             AndroidView(
                 modifier = Modifier.fillMaxSize(),
                 factory = { context ->
@@ -319,7 +374,7 @@ fun WebViewScreen(
                         //    kiosk couldn't iframe — keep the user inside the app)
                         //  - different host         → the phone's real browser
                         fun routeOutbound(url: String) {
-                            if (isSameHost(url, serverUrl)) {
+                            if (isSameNode(url)) {
                                 inAppUrl = url
                             } else {
                                 openExternalUrl(context, url)
@@ -458,7 +513,7 @@ fun WebViewScreen(
                                 error: android.net.http.SslError?,
                             ) {
                                 val u = error?.url
-                                if (u != null && isSameHost(u, serverUrl)) {
+                                if (u != null && isSameNode(u)) {
                                     handler?.proceed()
                                 } else {
                                     handler?.cancel()
@@ -595,7 +650,7 @@ fun WebViewScreen(
                         }
 
                         webView = this
-                        loadUrl(serverUrl)
+                        loadUrl(initialUrl)
                     }
                 },
             )
@@ -620,6 +675,7 @@ fun WebViewScreen(
                 InAppBrowser(
                     url = target,
                     serverUrl = serverUrl,
+                    meshUrl = meshFallbackUrl,
                     onClose = { inAppUrl = null },
                 )
             }
@@ -693,9 +749,14 @@ private fun fetchFavicon(pageUrl: String): Bitmap? {
 private fun InAppBrowser(
     url: String,
     serverUrl: String,
+    meshUrl: String? = null,
     onClose: () -> Unit,
 ) {
     val context = LocalContext.current
+    // Same-node check across BOTH node addresses (LAN + mesh ULA) — see the
+    // kiosk's isSameNode; a mismatch here bounced app links to the browser.
+    fun isSameNode(u: String): Boolean =
+        isSameHost(u, serverUrl) || (meshUrl != null && isSameHost(u, meshUrl))
     var browser by remember { mutableStateOf<WebView?>(null) }
     var title by remember { mutableStateOf(android.net.Uri.parse(url).host ?: url) }
     var favicon by remember { mutableStateOf<Bitmap?>(null) }
@@ -809,7 +870,7 @@ private fun InAppBrowser(
                                 error: android.net.http.SslError?,
                             ) {
                                 val u = error?.url
-                                if (u != null && isSameHost(u, serverUrl)) {
+                                if (u != null && isSameNode(u)) {
                                     handler?.proceed()
                                 } else {
                                     handler?.cancel()
@@ -823,7 +884,7 @@ private fun InAppBrowser(
                                 val u = request?.url?.toString() ?: return false
                                 // Stay in the overlay for same-node navigation;
                                 // hand genuinely external links to the real browser.
-                                if (isSameHost(u, serverUrl)) return false
+                                if (isSameNode(u)) return false
                                 openExternalUrl(ctx, u)
                                 return true
                             }