fix(playback): retain ReplayGain for SAF descriptor leases

Carry the original display name through playback leases to format-aware metadata reads. Cache successful normalization results by source identity, bound the cache, and retry transient read failures.

Add regressions for descriptor hints, album gain fallback, and failed-read retries.

android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt

@@ -838,6 +838,7 @@ class MainActivity: FlutterFragmentActivity() {
         return mapOf(
             "token" to token,
             "path" to "/proc/self/fd/${descriptor.fd}",
+            "display_name" to buildUriDisplayName(Uri.parse(uriStr)),
         )
     }