refactor(core): asset pipeline overhaul & dock removal

- Introduced IAsset interface and refactored asset loading/saving.
- Migrated TextureContentHeader to Ghost.Engine; updated usage.
- Rewrote AssetRegistry, AssetCatalog, ImportCoordinator for new asset flow.
- Added thread-safe ConcurrentHashSet utility.
- Improved EditorApplication folder management/init.
- Updated TextureAssetHandler/TextureProcessor for new import/export.
- Added EditorContentProvider for asset access.
- Updated AssetManager to use new AssetType enum; removed GCHandle.
- Removed all custom docking controls and templates.
- Deleted obsolete ViewModels/Pages (Console, Hierarchy, Inspector, Project).
- Renamed ProjectBrowser to ContentBrowser; updated references.
- Updated NuGet packages, Result conversions, and commit instructions.
- General cleanup: namespaces, dead code, structure.

src/Runtime/Ghost.Core/Common.cs

@@ -1,15 +1,2 @@
 namespace Ghost.Core;
 
-public enum AssetType : byte
-{
-    Texture = 0,
-    Mesh = 1,
-    Material = 2,
-    Shaders = 3,
-    Audio = 4,
-    Scene = 5,
-    Video = 6,
-    Json = 7,
-
-    Unknown = 64,
-}