fix: recover tracks after reinstall via MediaScanner; add version to startup log

Android clears OWNER_PACKAGE_NAME for all MediaStore entries when an app is
uninstalled. Files survive on disk in Documents/Nav/ but the ownership query
returns 0 rows after reinstall. Fix: if the first load finds nothing, call
MediaScannerConnection.scanFile() on Documents/Nav/. Because our app triggers
the scan, the MediaScanner re-registers each file with our package as owner,
restoring the query results on the immediate retry.

Also log BuildConfig.VERSION_NAME + VERSION_CODE in the startup message so
the build is identifiable directly from the in-app debug log.

https://claude.ai/code/session_01DNjbYxiC1cco83dArNGW3G

3 files changed, 47 insertions, 3 deletions

diff --git a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
index bfa285d..8609456 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
@@ -223,7 +223,7 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
         hudDepth.text = "—"
         applyUnitLabels()
 
-        NavLogger.i("app", "started")
+        NavLogger.i("app", "started v${BuildConfig.VERSION_NAME} (${BuildConfig.VERSION_CODE})")
         setupBottomSheet()
         setupBottomNavigation()
         setupHandlers()
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
index 3c5c9d5..bd79985 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackRepository.kt
@@ -107,10 +107,21 @@ class TrackRepository(context: Context) {
         if (!pastTracksLoaded) {
             pastTracksLoaded = true
             NavLogger.i("track", "getPastTracks: loading from storage (first call)")
-            val stored = storage.loadAllTracks()
+            var stored = storage.loadAllTracks()
             NavLogger.i("track", "getPastTracks: storage returned ${stored.size} tracks " +
                 "(points: ${stored.map { it.size }})")
-            // Merge: put stored tracks behind any in-memory tracks from this session
+
+            if (stored.isEmpty()) {
+                // Android clears OWNER_PACKAGE_NAME on uninstall; the files survive on
+                // disk but the MediaStore query finds nothing. Triggering a rescan via
+                // our app re-registers the files under our package name, restoring ownership.
+                NavLogger.i("track", "getPastTracks: 0 tracks — triggering MediaScanner rescan")
+                storage.triggerNavDirRescan()
+                stored = storage.loadAllTracks()
+                NavLogger.i("track", "getPastTracks: after rescan: ${stored.size} tracks " +
+                    "(points: ${stored.map { it.size }})")
+            }
+
             _pastTracks.addAll(stored)
             NavLogger.i("track", "getPastTracks: total in memory=${_pastTracks.size}")
         }
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
index 0951a38..59d7e53 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/track/TrackStorage.kt
@@ -2,11 +2,14 @@ package org.terst.nav.track
 
 import android.content.ContentValues
 import android.content.Context
+import android.media.MediaScannerConnection
 import android.net.Uri
 import android.os.Build
 import android.os.Environment
 import android.provider.MediaStore
 import android.util.Log
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlinx.coroutines.withTimeoutOrNull
 import org.terst.nav.ui.NavLogger
 import java.io.File
 import java.time.Instant
@@ -255,4 +258,34 @@ class TrackStorage(private val context: Context) {
                     ?.takeIf { it.isNotEmpty() }
             } ?: emptyList()
     }
+
+    // ── Post-reinstall recovery ───────────────────────────────────────────────
+
+    /**
+     * Asks the MediaScanner to re-index Documents/Nav/. When triggered by our
+     * app, the scanner re-registers each file with OWNER_PACKAGE_NAME set to
+     * our package, restoring ownership that Android clears on uninstall.
+     * After this returns, the MediaStore query in [loadAllTracks] will find
+     * the files again.
+     */
+    suspend fun triggerNavDirRescan() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) return
+        val navDir = File(
+            Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS),
+            "Nav"
+        )
+        NavLogger.i("track", "triggerNavDirRescan: scanning ${navDir.absolutePath}")
+        withTimeoutOrNull(10_000L) {
+            suspendCancellableCoroutine<Unit> { cont ->
+                MediaScannerConnection.scanFile(
+                    context,
+                    arrayOf(navDir.absolutePath),
+                    null
+                ) { path, uri ->
+                    NavLogger.i("track", "triggerNavDirRescan: done path=$path uri=$uri")
+                    if (cont.isActive) cont.resume(Unit)
+                }
+            }
+        } ?: NavLogger.e("track", "triggerNavDirRescan: timed out")
+    }
 }