Fix render pacing and profiler readback

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

docs/guide/core.md

@@ -56,7 +56,7 @@ await core.setProfiler(false);
 stop();
 ```
 
-`new YawnCore(canvas, { debug: true })` enables the same timestamp-query mode at startup. Timings describe physical GPU passes and actual compiled draw counts; compatible indexed draws over consecutive instances collapse into one command. The sidebar also reports canvas size and wall-clock completion time.
+`new YawnCore(canvas, { debug: true })` enables the same timestamp-query mode at startup. Samples are read back asynchronously, so profiling does not serialize the GPU queue. Timings describe physical GPU passes and actual compiled draw counts; compatible indexed draws over consecutive instances collapse into one command. The sidebar also reports canvas size and wall-clock readback latency.
 
 The saved **Forward benchmark** playground renders 138 logical objects and 4.5 million triangles. Add `&grid=32` to lower geometry density or `&overdraw=1` to stack the objects while diagnosing depth and fragment cost.
 

docs/guide/getting-started.md

@@ -24,7 +24,7 @@ const scene = new Scene(canvas, { hdr: true, fps: 60 });
 await scene.ready;
 ```
 
-`Scene` initializes conventional SOA rows and loads one clustered-forward HDR render graph. The core itself still starts with only its eight-float `info` row.
+Omit `fps` to render as fast as the browser and GPU allow. `Scene` initializes conventional SOA rows and loads one clustered-forward HDR render graph. The core itself still starts with only its eight-float `info` row.
 
 ## 3. Add a triangle