fix(metadata): recognize featured artist credits consistently

Handle feature and featured separators across display, Android finalization and Rust tag writing. Split conjunction credits only when separate artist IDs confirm them, and offer a picker for multi-artist navigation.

test/artist_utils_test.dart

@@ -2,6 +2,23 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:spotiflac_android/utils/artist_utils.dart';
 
 void main() {
+  test('featured variants and confirmed conjunction credits are clickable', () {
+    expect(splitArtistNames('One featured Two'), ['One', 'Two']);
+    expect(splitArtistNames('One feature Two'), ['One', 'Two']);
+    expect(primaryArtistTagValue('One featured Two'), 'One');
+    expect(primaryArtistTagValue('One feature Two'), 'One');
+    expect(splitArtistNames('One and Two', creditedArtistCount: 2), [
+      'One',
+      'Two',
+    ]);
+    expect(splitArtistNames('Florence and the Machine'), [
+      'Florence and the Machine',
+    ]);
+    expect(
+      splitArtistNames('Florence and the Machine', creditedArtistCount: 1),
+      ['Florence and the Machine'],
+    );
+  });
   test('primary artist prefers the first album artist', () {
     expect(
       primaryArtistName(