Implement core game functionality with AppRoot, SaveClient, PlayerRepository, and LevelRepository classes

game/repositories/LevelRepository.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Mr.BrickAdventures.game.repositories;
+
+public sealed class LevelRepository
+{
+    public int Current { get; private set; } = 0;
+    public HashSet<int> Unlocked { get; } = new() { 0 };
+    public HashSet<int> Completed { get; } = new();
+
+    public event Action<int>? CurrentChanged;
+
+    public void SetCurrent(int idx) { Current = idx; CurrentChanged?.Invoke(Current); }
+    public void Unlock(int idx) => Unlocked.Add(idx);
+    public void Complete(int idx) { Completed.Add(idx); Unlock(idx + 1); }
+
+    public LevelState Export() => new() {
+        Current = Current, Unlocked = [..Unlocked], Completed = [..Completed]
+    };
+    public void Load(LevelState s) {
+        Current = s.Current;
+        Unlocked.Clear(); foreach (var i in s.Unlocked) Unlocked.Add(i);
+        Completed.Clear(); foreach (var i in s.Completed) Completed.Add(i);
+        CurrentChanged?.Invoke(Current);
+    }
+}
+
+public record LevelState {
+    public int Current;
+    public int[] Unlocked = [];
+    public int[] Completed = [];
+}