Refactor project management and enhance architecture

Added a new static class `AssetsPath` for asset management.
Added a new icon file (`icon-256.ico`) for UI representation.
Added new package references to enhance functionality.
Added internals visibility attributes for better testing.
Added a new `EngineEditorViewModel` class for MVVM support.
Added a new `GameObject` class for component management.
Added a new `BitSet` class for efficient bit manipulation.
Added various utility classes to support the new entity system.

Changed the `ID` property in `ProjectInfo` to internal.
Changed the `AddProjectAsync` method to return the created `ProjectInfo`.
Changed the connection string retrieval method to use the new `Command` constant.
Changed the `DataPath` class to use `readonly` fields for folder paths.
Changed the `ActivationHandler` class to use new `DataPath` constants.
Changed the `OpenProjectPage` layout and interaction for better UI.

Updated the target framework to a newer version for compatibility.
Updated the `ProjectService` to use new constants from `DataPath`.
Updated the `World` class to improve entity management.

Refactored the `ProjectRepository` class to encapsulate SQL commands.
Refactored the `Transform` class to use properties for better encapsulation.

Ghost.Entities/Entity.cs

@@ -0,0 +1,93 @@
+using System.Runtime.CompilerServices;
+
+namespace Ghost.Entities;
+
+[SkipLocalsInit]
+public struct Entity : IEquatable<Entity>, IComparable<Entity>
+{
+    private const EntityID _WORLD_INDEX_BITS = 4u;
+    private const EntityID _GENERATION_BITS = 8u;
+    private const EntityID _INDEX_BITS = sizeof(EntityID) * 8 - _WORLD_INDEX_BITS - _GENERATION_BITS;
+
+    private const EntityID _WORLD_INDEX_MASK = (1u << (int)_WORLD_INDEX_BITS) - 1;
+    private const EntityID _GENERATION_MASK = (1u << (int)_GENERATION_BITS) - 1;
+    private const EntityID _INDEX_MASK = (1u << (int)_INDEX_BITS) - 1;
+    private const EntityID _ID_MASK = EntityID.MaxValue;
+
+    private EntityID _id;
+
+    public readonly bool IsValid
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        get => _id != _ID_MASK;
+    }
+
+    public readonly EntityID Index
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        get => _id & _INDEX_MASK;
+    }
+
+    public readonly GenerationID Generation
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        get => (GenerationID)(_id >> (int)_INDEX_BITS & _GENERATION_MASK);
+    }
+
+    public readonly WorldID WorldIndex
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        get => (WorldID)(_id >> (int)(_INDEX_BITS + _GENERATION_BITS) & _WORLD_INDEX_MASK);
+    }
+
+    public void IncrementGeneration()
+    {
+        var generation = Generation + 1u;
+        if (generation >= _GENERATION_MASK)
+        {
+            throw new InvalidOperationException("Generation overflow");
+        }
+
+        _id = _id & ~(_GENERATION_MASK << (int)_INDEX_BITS) | generation << (int)_INDEX_BITS;
+    }
+
+    internal Entity(EntityID index, EntityID generation, EntityID worldIndex)
+    {
+        _id = worldIndex << (int)(_INDEX_BITS + _GENERATION_BITS) | generation << (int)_INDEX_BITS | index;
+    }
+
+    public readonly bool Equals(Entity other)
+    {
+        return _id == other._id;
+    }
+
+    public readonly int CompareTo(Entity other)
+    {
+        return _id.CompareTo(other._id);
+    }
+
+    public override readonly bool Equals(object? obj)
+    {
+        return obj is Entity other && Equals(other);
+    }
+
+    public override readonly int GetHashCode()
+    {
+        return _id.GetHashCode();
+    }
+
+    public static bool operator ==(Entity left, Entity right)
+    {
+        return left.Equals(right);
+    }
+
+    public static bool operator !=(Entity left, Entity right)
+    {
+        return !(left == right);
+    }
+
+    public override readonly string ToString()
+    {
+        return $"Entity {{ Index: {Index}, Generation: {Generation}, WorldIndex: {WorldIndex} }}";
+    }
+}