feat(catalog): add Blue Sweater intro showcase (#630)

## Problem

The Blue Sweater intro HyperFrames project was only available as a standalone exported project zip. It was not installable from the public registry or visible in the Catalog Showcases group.

## What this fixes

Adds `blue-sweater-intro-video` as a registry block with its composition, avatar image, and sound mix asset. The block is exposed through the generated catalog page, `docs/public/catalog-index.json`, and the Showcases navigation.

The manifest and generated catalog page credit the creator as [Joe Sai](https://x.com/_blue_sweater_).

## Root cause

Catalog-visible blocks are driven by `registry/registry.json`, each block's `registry-item.json`, generated docs/catalog files, and CDN-hosted preview media. The exported project had a valid standalone composition, but it had not been converted into that registry/catalog contract or uploaded to the docs preview CDN.

## Verification

### Local checks

- `bun install`
- `bun run build`
- `bunx tsx scripts/generate-catalog-pages.ts`
- `bun run generate:catalog-previews -- --only blue-sweater-intro-video`
- `bun packages/cli/src/cli.ts add blue-sweater-intro-video --dir /tmp/hf-blue-sweater-install-test --no-clipboard --json` against a locally served registry
- `bun packages/cli/src/cli.ts lint /tmp/hf-blue-sweater-install-test` returned 0 errors and 3 static GSAP overlap warnings from the supplied timeline/parser path
- `bun packages/cli/src/cli.ts validate /tmp/hf-blue-sweater-install-test --timeout 5000` returned 0 runtime errors and 0 warnings, with contrast audit warnings only
- `bun packages/cli/src/cli.ts inspect /tmp/hf-blue-sweater-install-test --at 0.5,2.5,5.5,9.8,11.2 --json` returned 0 layout issues
- `bun packages/cli/src/cli.ts render /tmp/hf-blue-sweater-install-test --output /tmp/hf-blue-sweater-install-test/blue-sweater-intro-video-render.mp4 --fps 24 --quality draft --workers 3`
- `ffprobe` reported the installed render duration as `12.000000`
- `bunx oxfmt --check registry/registry.json registry/blocks/blue-sweater-intro-video/registry-item.json registry/blocks/blue-sweater-intro-video/blue-sweater-intro-video.html docs/docs.json docs/public/catalog-index.json docs/catalog/blocks/blue-sweater-intro-video.mdx`
- `git diff --check`
- `bunx vitest run packages/cli/src/commands/add.test.ts packages/core/src/registry/types.test.ts`

### Browser verification

- Started a real local HyperFrames preview for the installed test project.
- Used `agent-browser` to open `http://localhost:5198/api/projects/hf-blue-sweater-install-test/preview` at 1920x1080.
- Verified the runtime registered `install-test` and `blue-sweater-intro-video` timelines.
- Sought the block to the final card and verified `@_blue_sweater_` and the following state were visible.
- Recorded an `agent-browser`-driven full animation pass; `ffprobe` confirmed a 1920x1080 WebM with 110 video frames.
- Checked the fresh `agent-browser` session for page errors after the direct preview flow: `errors: []`.
- Used `agent-browser` to load an HTML page with the exact generated CDN `video`/`poster` URLs; the browser reported `readyState: 4`, `videoWidth: 1920`, `videoHeight: 1080`, and `paused: false`.

### CDN upload

Uploaded the generated preview media with AWS CLI to the existing docs image bucket path:

- `s3://heygen-public/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.mp4`
- `s3://heygen-public/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.png`

Verified both public CDN URLs return `HTTP 200` with correct content type and immutable cache headers:

- `https://static.heygen.ai/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.mp4` (`video/mp4`)
- `https://static.heygen.ai/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.png` (`image/png`)

## Notes

- Local-only browser proof artifacts:
  - `/tmp/hf-blue-sweater-browser-proof/fresh-final-card.png`
  - `/tmp/hf-blue-sweater-browser-proof/fresh-browser-flow.webm`
  - `/tmp/hf-blue-sweater-cdn-check.png`
- Local-only installed render artifact:
  - `/tmp/hf-blue-sweater-install-test/blue-sweater-intro-video-render.mp4`

docs/catalog/blocks/blue-sweater-intro-video.mdx

@@ -0,0 +1,48 @@
+---
+title: "Blue Sweater Intro Video"
+description: "Warm AI creator intro sequence that resolves into an X follow card for @_blue_sweater_."
+---
+
+# Blue Sweater Intro Video
+
+Warm AI creator intro sequence that resolves into an X follow card for @_blue_sweater_.
+
+`showcase` `ai` `creator` `sfx`
+
+Created by [Joe Sai](https://x.com/_blue_sweater_).
+
+<video className="w-full aspect-video rounded-xl object-cover bg-zinc-100 dark:bg-zinc-800" src="https://static.heygen.ai/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.mp4" poster="https://static.heygen.ai/hyperframes-oss/docs/images/catalog/blocks/blue-sweater-intro-video.png" autoPlay muted loop playsInline />
+
+## Install
+
+<CodeGroup>
+
+```bash Terminal
+npx hyperframes add blue-sweater-intro-video
+```
+
+</CodeGroup>
+
+## Details
+
+| Property | Value |
+| --- | --- |
+| Type | Block |
+| Dimensions | 1920×1080 |
+| Duration | 12s |
+
+## Files
+
+| File | Target | Type |
+| --- | --- | --- |
+| `blue-sweater-intro-video.html` | `compositions/blue-sweater-intro-video.html` | hyperframes:composition |
+| `assets/joe-sai-avatar.png` | `assets/joe-sai-avatar.png` | hyperframes:asset |
+| `assets/sfx/integrated-melodic-tech-mix.wav` | `assets/sfx/integrated-melodic-tech-mix.wav` | hyperframes:asset |
+
+## Usage
+
+After installing, add the block to your host composition:
+
+```html
+<div data-composition-id="blue-sweater-intro-video" data-composition-src="compositions/blue-sweater-intro-video.html" data-start="0" data-duration="12" data-track-index="1" data-width="1920" data-height="1080"></div>
+```