feat: Implement TTS playback store and enhance reading progress synchronization

- Added ReaderTtsPlaybackStore to manage TTS start requests with a maximum of 4 pending requests.
- Updated app configuration to use a production API URL.
- Enhanced BookmarkModel to infer type when not provided by the API for backward compatibility.
- Introduced methods in LocalStore for saving, loading, and clearing the last route path.
- Implemented syncProgress method in BookshelfNotifier to update reading progress and bookmarks from the server.
- Modified ReaderScreen to handle chapter navigation and TTS playback more effectively, including auto-start logic.
- Updated TtsPlayerWidget to accept additional parameters for chapter navigation.
- Enhanced TtsNotifier to handle new parameters for TTS requests and manage playback state.
- Improved SplashScreen to restore the last visited route after splash screen display.

lib/core/models/bookmark_model.dart

@@ -39,13 +39,28 @@ class BookmarkModel extends Equatable {
   factory BookmarkModel.fromJson(Map<String, dynamic> json) => BookmarkModel(
         id: json['id'] as String,
         novelId: json['novelId'] as String,
-        type: BookmarkType.fromString(json['type'] as String?),
         lastChapterId: json['lastChapterId'] as String?,
         lastChapterNumber: json['lastChapterNumber'] as int?,
         readChapters: (json['readChapters'] as List<dynamic>?)
                 ?.map((e) => (e as num).toInt())
                 .toList() ??
             [],
+        type: () {
+          final explicitType = BookmarkType.fromString(json['type'] as String?);
+          if ((json['type'] as String?) != null) {
+            return explicitType;
+          }
+
+          // Backward-compatible inference when API does not return `type`.
+          final inferredLastChapter = json['lastChapterNumber'] as int?;
+          final inferredReadChapters = (json['readChapters'] as List<dynamic>?)
+                  ?.map((e) => (e as num).toInt())
+                  .toList() ??
+              const <int>[];
+          return (inferredLastChapter != null || inferredReadChapters.isNotEmpty)
+              ? BookmarkType.reading
+              : BookmarkType.bookmarked;
+        }(),
         novel: json['novel'] != null
             ? NovelModel.fromJson(json['novel'] as Map<String, dynamic>)
             : null,