Strip core to render data and render graphs

Move glTF, picking, camera controls, and conventional handles into addons. Keep camera and material mutations in SIMD-aligned shared SOA rows and synchronize material updates directly into GPU buffers.

Amp-Thread-ID: https://ampcode.com/threads/T-01a01380-b478-77d0-84a0-102880a5c5ae
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

examples/cookbook/17-conventional-handles.js

@@ -0,0 +1,19 @@
+import { CameraHandle, MaterialHandles, MeshHandles } from "@yawn/mesh-handles";
+
+/** Wrap one import result in the conventional object API without hiding core. */
+export function conventionalSceneHandles(core, imported) {
+  return {
+    camera: new CameraHandle(core),
+    meshes: new MeshHandles(core).fromImportedScene(imported),
+    materials: new MaterialHandles(core).fromImportedScene(imported),
+  };
+}
+
+/** Property assignments remain direct SAB writes; no camera/material message is sent. */
+export function restyleScene({ camera, materials }) {
+  camera.lookAt([4, 3, 6], [0, 0, 0]);
+  if (materials[0]) {
+    materials[0].baseColor = [0.2, 0.55, 1, 1];
+    materials[0].roughness = 0.35;
+  }
+}