feat(tv-ui): add slideshow pattern mode and improve admin readability

lib/data/local/models.dart

@@ -8,6 +8,16 @@ class HiveBoxes {
   static const String hijriCache = 'hijri_cache';
 }
 
+class SlideshowPatternMode {
+  SlideshowPatternMode._();
+
+  static const String alternating = 'alternating';
+  static const String burst = 'burst';
+
+  static bool isValid(String value) =>
+      value == alternating || value == burst;
+}
+
 /// AppSettings stored in Hive.
 @HiveType(typeId: 0)
 class AppSettings extends HiveObject {
@@ -94,6 +104,16 @@ class AppSettings extends HiveObject {
   @HiveField(34)
   int announcementSlideDurationSec;
 
+  // Slideshow pattern mode:
+  // - alternating: main-1-main-2-main...
+  // - burst: main-1-2-main-3-4... (N slides between main phases)
+  @HiveField(38)
+  String slideshowPatternMode;
+
+  // Number of slideshow slides shown between main phases when mode=burst.
+  @HiveField(39)
+  int slideshowSlidesPerMain;
+
   // Slideshow image paths (local)
   @HiveField(20)
   List<String> slideshowImages;
@@ -180,6 +200,8 @@ class AppSettings extends HiveObject {
     this.lastAutoSyncAttemptDate,
     this.mainCenterSlideDurationSec = 10,
     this.announcementSlideDurationSec = 7,
+    this.slideshowPatternMode = SlideshowPatternMode.alternating,
+    this.slideshowSlidesPerMain = 2,
     this.slideshowImages = const [],
     this.textScaleIndex = 1,
     this.useUnsplashBackground = false,
@@ -221,6 +243,8 @@ class AppSettings extends HiveObject {
     String? lastAutoSyncAttemptDate,
     int? mainCenterSlideDurationSec,
     int? announcementSlideDurationSec,
+    String? slideshowPatternMode,
+    int? slideshowSlidesPerMain,
     List<String>? slideshowImages,
     int? textScaleIndex,
     bool? useUnsplashBackground,
@@ -265,6 +289,10 @@ class AppSettings extends HiveObject {
           mainCenterSlideDurationSec ?? this.mainCenterSlideDurationSec,
       announcementSlideDurationSec:
           announcementSlideDurationSec ?? this.announcementSlideDurationSec,
+      slideshowPatternMode:
+          slideshowPatternMode ?? this.slideshowPatternMode,
+      slideshowSlidesPerMain:
+          slideshowSlidesPerMain ?? this.slideshowSlidesPerMain,
       slideshowImages: slideshowImages ?? this.slideshowImages,
       textScaleIndex: textScaleIndex ?? this.textScaleIndex,
       useUnsplashBackground:
@@ -299,6 +327,7 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
       fields[reader.readByte()] = reader.read();
     }
     final runningTexts = (fields[14] as List?)?.cast<String>() ?? const [];
+    final storedPatternMode = (fields[38] as String?)?.trim() ?? '';
     return AppSettings(
       masjidName: fields[0] as String? ?? 'Masjid Al-Ikhlas',
       masjidAddress: fields[1] as String? ?? 'Jl. Kebaikan No. 1',
@@ -325,6 +354,11 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
       lastAutoSyncAttemptDate: fields[32] as String?,
       mainCenterSlideDurationSec: fields[33] as int? ?? 10,
       announcementSlideDurationSec: fields[34] as int? ?? 7,
+      slideshowPatternMode: SlideshowPatternMode.isValid(storedPatternMode)
+          ? storedPatternMode
+          : SlideshowPatternMode.alternating,
+      slideshowSlidesPerMain:
+          ((fields[39] as int?) ?? 2).clamp(1, 20).toInt(),
       slideshowImages: (fields[20] as List?)?.cast<String>() ?? const [],
       textScaleIndex: fields[21] as int? ?? 1,
       useUnsplashBackground: fields[22] as bool? ?? false,
@@ -345,7 +379,7 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
   @override
   void write(BinaryWriter writer, AppSettings obj) {
     writer
-      ..writeByte(38)
+      ..writeByte(40)
       ..writeByte(0)
       ..write(obj.masjidName)
       ..writeByte(1)
@@ -394,6 +428,10 @@ class AppSettingsAdapter extends TypeAdapter<AppSettings> {
       ..write(obj.mainCenterSlideDurationSec)
       ..writeByte(34)
       ..write(obj.announcementSlideDurationSec)
+      ..writeByte(38)
+      ..write(obj.slideshowPatternMode)
+      ..writeByte(39)
+      ..write(obj.slideshowSlidesPerMain)
       ..writeByte(20)
       ..write(obj.slideshowImages)
       ..writeByte(21)