feat(mobile): advance Paca.Mobile to production excellence with rich design assets and core systems

- Generate high-resolution glassmorphism app icon and splash screen assets
- Implement MobileIconSystem with semantic SF Symbols/Material glyph mappings
- Add OLEDBlack theme and contrast tokens to MobileThemeSystem
- Implement VideoSnifferParser.NegotiateBestQuality for multi-stream quality resolution
- Enhance DiscoverPage, FavoritesPage, and SyncSettingsPage with production controls
- Add Gate 103-114 test suites with 100% test pass rate

src/Paca.Mobile.Core/MobileNavigationModel.cs

@@ -0,0 +1,45 @@
+using System.Collections.Generic;
+
+namespace Paca.Mobile.Core;
+
+/// <summary>모바일 바텀 내비게이션 탭 종류</summary>
+public enum MobileTabKind
+{
+    Queue,
+    Discover,
+    Browser,
+    Favorites,
+    SyncSettings
+}
+
+/// <summary>모바일 탭 아이템 모델</summary>
+public class MobileTabItem
+{
+    public MobileTabKind Kind { get; }
+    public string Title { get; }
+    public string IconGlyph { get; }
+    public int BadgeCount { get; set; }
+
+    public MobileTabItem(MobileTabKind kind, string title, string iconGlyph)
+    {
+        Kind = kind;
+        Title = title;
+        IconGlyph = iconGlyph;
+    }
+}
+
+/// <summary>모바일 네비게이션 모델</summary>
+public static class MobileNavigationModel
+{
+    public static List<MobileTabItem> GetDefaultTabs()
+    {
+        return new List<MobileTabItem>
+        {
+            new(MobileTabKind.Queue, "대기열", MobileIconSystem.Queue),
+            new(MobileTabKind.Discover, "탐색", MobileIconSystem.Discover),
+            new(MobileTabKind.Browser, "브라우저", MobileIconSystem.Browser),
+            new(MobileTabKind.Favorites, "보관함", MobileIconSystem.Favorites),
+            new(MobileTabKind.SyncSettings, "동기화", MobileIconSystem.SyncSettings)
+        };
+    }
+}