feat(companion): share-the-app from Mesh Party + party entry on the intro screen — 0.5.8

- Party screen 'Share this app': shares this install's own APK through
  the system sheet (FileProvider over cache/share/), so a nearby friend
  gets the companion via Quick Share/Bluetooth with zero internet — the
  party-mode premise end to end.
- Intro screen: Mesh Party button under Get Started — party works with
  no node at all, so it belongs on the first screen a fresh install
  shows.
- Served APK: 0.5.8 (vc28), ready for the QR/OTA/ISO cut.

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 = 27
+        versionCode = 28
-        versionName = "0.5.7"
+        versionName = "0.5.8"
 
         vectorDrawables {
             useSupportLibrary = true

Android/app/src/main/AndroidManifest.xml

@@ -23,6 +23,18 @@
         android:usesCleartextTraffic="true"
         tools:targetApi="35">
 
+        <!-- Party-screen "Share this app": exposes the copied APK from
+             cache/share/ to the system share sheet, nothing else. -->
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
         <activity
             android:name=".MainActivity"
             android:exported="true"

Android/app/src/main/java/com/archipelago/app/ui/navigation/NavGraph.kt

@@ -126,6 +126,9 @@ fun AppNavHost(
     ) {
         composable(Routes.INTRO) {
             IntroScreen(
+                onMeshParty = {
+                    navController.navigate(Routes.MESH_PARTY)
+                },
                 onContinue = {
                     scope.launch {
                         prefs.markIntroSeen()

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

@@ -55,7 +55,12 @@ import com.archipelago.app.ui.theme.TextPrimary
 import kotlinx.coroutines.delay
 
 @Composable
-fun IntroScreen(onContinue: () -> Unit) {
+fun IntroScreen(
+    onContinue: () -> Unit,
+    // Mesh Party works with no node at all (phone↔phone) — offered right on
+    // the first screen so a friend who just got the app can join a party.
+    onMeshParty: () -> Unit = {},
+) {
     val logoAlpha = remember { Animatable(0f) }
     var showContent by remember { mutableStateOf(false) }
 
@@ -143,6 +148,14 @@ fun IntroScreen(onContinue: () -> Unit) {
                         onClick = onContinue,
                         modifier = Modifier.fillMaxWidth().height(56.dp),
                     )
+
+                    Spacer(modifier = Modifier.height(12.dp))
+
+                    GlassButton(
+                        text = stringResource(R.string.mesh_party),
+                        onClick = onMeshParty,
+                        modifier = Modifier.fillMaxWidth().height(48.dp),
+                    )
                 }
             }
         }

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

@@ -281,6 +281,16 @@ fun PartyScreen(
                 )
             }
             Spacer(Modifier.height(12.dp))
+            // Hand the app itself to a friend: shares this install's own APK
+            // through the system sheet (Quick Share/Bluetooth), so a nearby
+            // phone gets the companion with zero internet — the whole party
+            // premise.
+            GlassButton(
+                text = "Share this app",
+                onClick = { shareCompanionApk(context) },
+                modifier = Modifier.fillMaxWidth().height(48.dp),
+            )
+            Spacer(Modifier.height(12.dp))
         }
 
         // Party QR scanner overlay
@@ -364,3 +374,28 @@ private fun renderQr(payload: String, size: Int = 640): Bitmap? = try {
 } catch (_: Exception) {
     null
 }
+
+/** Share this install's own APK via the system share sheet — a nearby friend
+ *  gets the companion with no internet at all (Quick Share / Bluetooth). */
+private fun shareCompanionApk(context: android.content.Context) {
+    try {
+        val src = java.io.File(context.applicationInfo.sourceDir)
+        val dir = java.io.File(context.cacheDir, "share").apply { mkdirs() }
+        val out = java.io.File(dir, "archipelago-companion.apk")
+        src.copyTo(out, overwrite = true)
+        val uri = androidx.core.content.FileProvider.getUriForFile(
+            context, "${context.packageName}.fileprovider", out,
+        )
+        val send = android.content.Intent(android.content.Intent.ACTION_SEND).apply {
+            type = "application/vnd.android.package-archive"
+            putExtra(android.content.Intent.EXTRA_STREAM, uri)
+            addFlags(android.content.Intent.FLAG_GRANT_READ_URI_PERMISSION)
+        }
+        context.startActivity(
+            android.content.Intent.createChooser(send, "Share Archipelago Companion")
+                .addFlags(android.content.Intent.FLAG_ACTIVITY_NEW_TASK),
+        )
+    } catch (_: Exception) {
+        // No share targets / copy failed — nothing sensible to do here.
+    }
+}

Android/app/src/main/res/values/strings.xml

@@ -11,6 +11,7 @@
     <string name="welcome_title">Your Sovereign\nPersonal Server</string>
     <string name="welcome_subtitle">Bitcoin node, app platform, and private cloud — all in one box you control.</string>
     <string name="get_started">Get Started</string>
+    <string name="mesh_party">Mesh Party</string>
     <string name="use_https">Use HTTPS</string>
     <string name="port_label">Port (optional)</string>
     <string name="saved_servers">Saved Servers</string>

Android/app/src/main/res/xml/file_paths.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- FileProvider scope for the party-screen "Share this app" APK handoff. -->
+<paths>
+    <cache-path name="share" path="share/" />
+</paths>