docs: keep the audio on the Huly launch film

I stripped the audio track with -an when encoding for the web. The source has a
real mix at -19.2 dB mean / -3.1 dB peak, and the docs player is click-to-play,
so there is no reason for it to be silent. Re-encoded with AAC at 128k; levels
match the source exactly.

The other published films have no audio track at all to preserve — they were
rendered silent at source.

docs/concepts/frame-adapters.mdx

@@ -14,6 +14,26 @@ Most composition authors do not implement this interface. HyperFrames already se
 
 Use `FrameAdapter` when you are building a custom host around a seekable animation object.
 
+Rendering never plays the animation. It asks for one frame, waits, captures it,
+then asks for the next — so the same frame always comes out the same.
+
+```mermaid
+sequenceDiagram
+    participant R as Renderer
+    participant A as Frame adapter
+    participant T as Your timeline
+    R->>A: getDurationFrames()
+    A-->>R: 120
+    loop every frame, in any order
+        R->>A: seekFrame(90)
+        A->>T: jump to 3.0s and settle
+        T-->>A: state at 3.0s
+        A-->>R: ready
+        R->>R: capture the pixels
+    end
+    R->>A: destroy()
+```
+
 ## Interface
 
 ```ts

docs/guides/product-launch-video.mdx

@@ -11,7 +11,7 @@ Give HyperFrames the real URL when the product, website, or brand should appear
 <Frame caption="Made from huly.io with this workflow — the product's own screens, its type and color, cut into a launch film.">
   <DocsVideo
     title="A Huly product-launch film created with HyperFrames from the live site"
-    src="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/product-launch-huly-v2.mp4"
+    src="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/product-launch-huly-v3.mp4"
     poster="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/product-launch-huly-v2.jpg"
   />
 </Frame>