feat: Implement 3D system and procedural texture manager

- Extended mini_math.h with mat4 multiplication and affine transforms.
- Implemented TextureManager for runtime procedural texture generation and GPU upload.
- Added 3D system components: Camera, Object, Scene, and Renderer3D.
- Created test_3d_render mini-demo for interactive 3D verification.
- Fixed WebGPU validation errors regarding depthSlice and unimplemented WaitAny.

1 files changed, 3 insertions, 0 deletions

diff --git a/GEMINI.md b/GEMINI.md
index 2bc669e..c50f1ff 100644
--- a/GEMINI.md
+++ b/GEMINI.md
@@ -5,6 +5,9 @@
 @FETCH_DEPS.md
 @CONTRIBUTING.md
 @HOWTO.md
+@3D.md
+@SPEC_EDITOR.md
+@PROCEDURAL.md
 @src/util/asset_manager.h
 @tools/asset_packer.cc
 @tools/spectool.cc