docs: ship the explainer film and make its project the running example

The introduction now plays a film built for it rather than an older showcase
clip: one request - "make a 30-second launch video for our new pricing page" -
carried through the agent building the project, Studio opening it, a person
changing one line, and the export finishing. It was produced with HyperFrames.

Hosting solved without the CDN. The clip sits in docs/images/showcase/ at 332KB,
under the repository's 500KB non-LFS limit, because the hero autoplays muted and
therefore does not need the audio track. Encoding it silently at 720p bought the
whole 42 seconds for less than the size of one catalog preview. The master with
its music bed still needs the shared asset host, and the SSO credentials for that
bucket have expired, so it stays out of the repo for now.

The quickstart's leading example is now that same pricing-page request, and says
so. Using a different example on every page forces the reader to rebuild the
mental model each time; one project carried across the pages is the cheapest
change available that makes them read as a single path.

Author: ukimsanov

docs/introduction.mdx

@@ -4,11 +4,11 @@ sidebarTitle: "What HyperFrames is"
 description: "Tell an AI agent what you want. It builds a real, editable video project — you refine it in Studio and export the film."
 ---
 
-<Frame caption="Made with HyperFrames, from a single request.">
+<Frame caption="One request — “make a 30-second launch video for our new pricing page” — from prompt to exported film. Made with HyperFrames.">
   <video
     className="aspect-video w-full object-cover bg-zinc-100 dark:bg-zinc-900"
-    src="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/hyperframes-launch-preview.mp4"
-    poster="https://static.heygen.ai/hyperframes-oss/docs/images/showcase/hyperframes-launch-poster.jpg"
+    src="/images/showcase/what-is-hyperframes.mp4"
+    poster="/images/showcase/what-is-hyperframes-poster.jpg"
     autoPlay
     muted
     loop

docs/quickstart.mdx

@@ -13,11 +13,14 @@ Use the closest example. You can change its wording before sending it.
 
 <Tabs>
   <Tab title="A product or website">
+    This is the request behind the film on [What HyperFrames is](/introduction) — the
+    same project is used as the example throughout these pages.
+
     ```text
-    /hyperframes Make a 30-second launch video for https://example.com.
-    It is for small design teams. Show the real product interface, focus on
-    how quickly a team can share a result, and end with “Try it together.”
-    Keep the pacing calm and premium.
+    /hyperframes Make a 30-second launch video for our new pricing page
+    at https://example.com/pricing. It is for small design teams. Show the
+    real product interface, focus on how quickly a team can share a result,
+    and end with “Try it together.” Keep the pacing calm and premium.
     ```
   </Tab>
   <Tab title="Notes or an idea">