refactor: rewrite scene streaming & shader bridge

This commit overhauls the scene management and streaming architecture to use a chunk-based asynchronous loading paradigm, and completely decouples the graphics runtime from editor compilation services to eliminate circular dependencies.

Shader Bridge Decoupling:
- Resolved circular runtime dependency between Ghost.Graphics and Ghost.Editor.Core.
- Shifted EditorShaderCompilerBridge from querying EngineCore to a decoupled event-driven model using IShaderCompilationBridge.
- Introduced custom stack-friendly delegate ShaderVariantCompiledHandler to handle ReadOnlySpan<ShaderByteCode> compilation buffers while maintaining zero-allocation constraints.
- Updated ShaderLibrary to self-manage bytecode caching and stale pipeline eviction by listening to compiler events.

Scene & Streaming Overhaul:
- Re-implemented Scene.cs with a high-performance two-phase asynchronous scene loading architecture.
- Replaced outdated per-entity component processing with chunk-level shared data management using the ISharedComponent paradigm for SceneID.
- Optimized ECS Query.cs and Archetype.cs to handle streaming chunk operations efficiently.
- Updated AssetManager, ResourceStreamingProcessor, and asset entries (SceneAssetEntry, MeshAssetEntry, TextureAssetEntry) to support the new streaming workflow.

.gitignore

@@ -13,7 +13,7 @@
 AGENTS.md
 .opencode/
 .code-review-graph/
-.github/instructions/
+.antigravitycli/
 
 ref/
 docfx/