feat: Enhance TTS player functionality and UI

- Added resume functionality to TTS player when paused.
- Display voice name or language in TTS player UI.
- Improved error handling in reader provider with debug messages.
- Updated TTS service to configure Vietnamese voice and handle platform-specific audio settings.
- Removed wakelock dependency and related code.
- Fixed search screen error handling.
- Updated settings screen to navigate to home after sign out.
- Improved splash screen with timer management.
- Enhanced main app error handling with logging.
- Removed unused package_info_plus and wakelock_plus dependencies.
- Added environment variable support for mobile runtime.
- Integrated Google Sign-In configuration for Android.
- Created logging observer for Riverpod providers.
- Added scripts for environment setup and Google Sign-In validation.

lib/core/models/reading_settings.dart

@@ -4,24 +4,40 @@ class ReadingSettings {
     this.lineHeight = 1.8,
     this.letterSpacing = 0,
     this.fontFamily = 'serif',
+    this.themePreset = 'paper',
+    this.horizontalPadding = 20,
+    this.paragraphSpacing = 24,
+    this.textAlign = 'justify',
   });
 
   final double fontSize;
   final double lineHeight;
   final double letterSpacing;
   final String fontFamily;
+  final String themePreset;
+  final double horizontalPadding;
+  final double paragraphSpacing;
+  final String textAlign;
 
   ReadingSettings copyWith({
     double? fontSize,
     double? lineHeight,
     double? letterSpacing,
     String? fontFamily,
+    String? themePreset,
+    double? horizontalPadding,
+    double? paragraphSpacing,
+    String? textAlign,
   }) =>
       ReadingSettings(
         fontSize: fontSize ?? this.fontSize,
         lineHeight: lineHeight ?? this.lineHeight,
         letterSpacing: letterSpacing ?? this.letterSpacing,
         fontFamily: fontFamily ?? this.fontFamily,
+        themePreset: themePreset ?? this.themePreset,
+        horizontalPadding: horizontalPadding ?? this.horizontalPadding,
+        paragraphSpacing: paragraphSpacing ?? this.paragraphSpacing,
+        textAlign: textAlign ?? this.textAlign,
       );
 
   factory ReadingSettings.fromJson(Map<String, dynamic> json) => ReadingSettings(
@@ -29,6 +45,10 @@ class ReadingSettings {
         lineHeight: (json['lineHeight'] as num?)?.toDouble() ?? 1.8,
         letterSpacing: (json['letterSpacing'] as num?)?.toDouble() ?? 0,
         fontFamily: json['fontFamily'] as String? ?? 'serif',
+        themePreset: json['themePreset'] as String? ?? 'paper',
+        horizontalPadding: (json['horizontalPadding'] as num?)?.toDouble() ?? 20,
+        paragraphSpacing: (json['paragraphSpacing'] as num?)?.toDouble() ?? 24,
+        textAlign: json['textAlign'] as String? ?? 'justify',
       );
 
   Map<String, dynamic> toJson() => {
@@ -36,5 +56,9 @@ class ReadingSettings {
         'lineHeight': lineHeight,
         'letterSpacing': letterSpacing,
         'fontFamily': fontFamily,
+        'themePreset': themePreset,
+        'horizontalPadding': horizontalPadding,
+        'paragraphSpacing': paragraphSpacing,
+        'textAlign': textAlign,
       };
 }