Fix GPX file opening, share sheet visibility, and add SAF track storage

Intent filter fixes:
- Remove pathSuffix=".gpx" + scheme restriction from the application/octet-stream
  ACTION_VIEW filter; pathSuffix matches the URI path, not the filename, so it
  never fired against file manager content URIs (opaque paths like /provider/uuid).
  The existing display-name check in handleIncomingGpx() is the correct gate.
- Add ACTION_SEND filter for application/octet-stream; Nav was invisible in share
  sheets because most file managers send this type for .gpx files.

SAF-based track storage (API 29+):
- Replace fragile SharedPrefs URI cache + OWNER_PACKAGE_NAME MediaStore query with
  Storage Access Framework as the primary write/read path. The user grants access to
  their tracks folder once via ACTION_OPEN_DOCUMENT_TREE; DocumentFile.listFiles()
  finds all GPX files without relying on MediaStore ownership (which Android clears
  on uninstall). After reinstall, a one-tap "Restore track access" button in Saved
  Tracks re-authorizes the same folder and all tracks immediately reappear.
- MediaStore path (existing) is kept as fallback for tracks saved before this change
- Add SafState enum (CONFIGURED / PERMISSION_LOST / NOT_CONFIGURED) in TrackStorage
- TrackRepository exposes safState() and initSafDirectory() thin wrappers
- MainViewModel exposes safState StateFlow and onSafDirectorySelected()
- SavedTracksFragment observes safState and shows contextual setup / re-auth button
- MainActivity registers safPickerLauncher and exposes launchSafPicker()
- Add androidx.documentfile:documentfile:1.0.1 dependency

https://claude.ai/code/session_01YUbuZNDAoLea4cf9UGQ9qn

1 files changed, 11 insertions, 9 deletions

diff --git a/android-app/app/src/main/AndroidManifest.xml b/android-app/app/src/main/AndroidManifest.xml
index 5090190..23817bb 100644
--- a/android-app/app/src/main/AndroidManifest.xml
+++ b/android-app/app/src/main/AndroidManifest.xml
@@ -56,20 +56,17 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="application/xml" />
             </intent-filter>
-            <!-- Google Files on Android 16 sends application/octet-stream for .gpx because
-                 MimeTypeMap has no entry for that extension. The ExternalStorageProvider URI
-                 encodes the full file path, so pathSuffix=".gpx" keeps this targeted.
-                 Code double-checks via OpenableColumns.DISPLAY_NAME before parsing. -->
+            <!-- Many file managers send application/octet-stream with no path hints.
+                 pathSuffix cannot match content URIs (opaque paths); code checks
+                 OpenableColumns.DISPLAY_NAME instead. -->
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
                 <category android:name="android.intent.category.DEFAULT" />
-                <data android:scheme="content" android:mimeType="application/octet-stream"
-                    android:pathSuffix=".gpx" />
+                <data android:mimeType="application/octet-stream" />
             </intent-filter>
 
-            <!-- Share-sheet filters (ACTION_SEND): file URI is in EXTRA_STREAM, not
-                 intent data, so pathSuffix can't help — these cover apps that type .gpx
-                 correctly. Code checks display name for the XML variants. -->
+            <!-- Share-sheet filters (ACTION_SEND): file URI is in EXTRA_STREAM.
+                 Code checks display name for XML and octet-stream variants. -->
             <intent-filter>
                 <action android:name="android.intent.action.SEND" />
                 <category android:name="android.intent.category.DEFAULT" />
@@ -90,6 +87,11 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="application/xml" />
             </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="application/octet-stream" />
+            </intent-filter>
         </activity>
     </application>
 </manifest>