fix: resolve folder navigation and image display bugs in nested mixed libraries

- Exclude TV Series, Seasons, Collections, and Playlists from navigable folders in FolderBrowseViewModel.
- Clicking Series/Seasons/Collections/Playlists in folder views now opens their native detailed screens.
- Prioritize Primary (poster) images over Thumb (landscape) images in FolderBrowseScreen for media items.
- Fix audio migration unit test key mismatch (v1 -> v2) to ensure a clean test run.

Author: mattsigal

lib/data/viewmodels/folder_browse_view_model.dart

@@ -208,17 +208,24 @@ class FolderBrowseViewModel extends ChangeNotifier {
 
   bool isNavigableFolder(AggregatedItem item) {
     final type = item.type;
+    if (type == 'Series' ||
+        type == 'Season' ||
+        type == 'BoxSet' ||
+        type == 'Playlist') {
+      return false;
+    }
+
+    final isFolder = item.rawData['IsFolder'] as bool? ?? false;
+    if (isFolder) return true;
+
     return type == 'Folder' ||
         type == 'CollectionFolder' ||
         type == 'UserView' ||
-        type == 'BoxSet' ||
         type == 'MusicAlbum' ||
-        type == 'Season' ||
-        type == 'Series' ||
-        type == 'PhotoAlbum' ||
-        type == 'Playlist';
+        type == 'PhotoAlbum';
   }
 
+
   @override
   void dispose() {
     _disposed = true;

lib/ui/screens/browse/folder_browse_screen.dart

@@ -71,30 +71,56 @@ class _FolderBrowseScreenState extends State<FolderBrowseScreen> {
 
   String? _imageUrl(AggregatedItem item, {int? maxWidth}) {
     final api = _vm.imageApi;
+    final isFolder = _vm.isNavigableFolder(item);
 
     final imageTags = item.rawData['ImageTags'];
     if (imageTags is Map) {
-      final thumbTag = imageTags['Thumb'] as String?;
-      if (thumbTag != null) {
-        return api.getThumbImageUrl(item.id, maxWidth: maxWidth, tag: thumbTag);
-      }
-
-      final primaryTag = imageTags['Primary'] as String?;
-      if (primaryTag != null) {
-        return api.getPrimaryImageUrl(
-          item.id,
-          maxWidth: maxWidth,
-          tag: primaryTag,
-        );
-      }
-
-      final backdropTag = imageTags['Backdrop'] as String?;
-      if (backdropTag != null) {
-        return api.getBackdropImageUrl(
-          item.id,
-          maxWidth: maxWidth,
-          tag: backdropTag,
-        );
+      if (isFolder) {
+        final thumbTag = imageTags['Thumb'] as String?;
+        if (thumbTag != null) {
+          return api.getThumbImageUrl(item.id, maxWidth: maxWidth, tag: thumbTag);
+        }
+
+        final primaryTag = imageTags['Primary'] as String?;
+        if (primaryTag != null) {
+          return api.getPrimaryImageUrl(
+            item.id,
+            maxWidth: maxWidth,
+            tag: primaryTag,
+          );
+        }
+
+        final backdropTag = imageTags['Backdrop'] as String?;
+        if (backdropTag != null) {
+          return api.getBackdropImageUrl(
+            item.id,
+            maxWidth: maxWidth,
+            tag: backdropTag,
+          );
+        }
+      } else {
+        final primaryTag = imageTags['Primary'] as String?;
+        if (primaryTag != null) {
+          return api.getPrimaryImageUrl(
+            item.id,
+            maxWidth: maxWidth,
+            tag: primaryTag,
+          );
+        }
+
+        final thumbTag = imageTags['Thumb'] as String?;
+        if (thumbTag != null) {
+          return api.getThumbImageUrl(item.id, maxWidth: maxWidth, tag: thumbTag);
+        }
+
+        final backdropTag = imageTags['Backdrop'] as String?;
+        if (backdropTag != null) {
+          return api.getBackdropImageUrl(
+            item.id,
+            maxWidth: maxWidth,
+            tag: backdropTag,
+          );
+        }
       }
     }