Render only when shared state changes

Add shared-data and bundle invalidation signals, and have handles publish them automatically for SAB and graph mutations.

Document the raw core worker protocol in a dedicated VitePress site and simplify the glTF import and picking example.

Amp-Thread-ID: https://ampcode.com/threads/T-01a01ff8-b91f-724f-8952-f07c6b5042fd
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

docs/.vitepress/Playground.vue

@@ -183,7 +183,7 @@ function sampleFps(time = performance.now()) {
   try {
     const core = current?.scene?.core ?? current?.core;
     if (!core) throw new Error();
-    const frame = Number(core.array("info").row(0)[1]);
+    const frame = Number(core.array("signals").row(0)[1]);
     if (frame < sampledFrame) sampledAt = 0;
     if (!sampledAt) {
       sampledFrame = frame;