feat: add the FixMap launch film to docs and site

[aryamthecodebreaker]

What changed

• add the supplied 23.6-second FixMap launch film and a generated poster frame to the web app
• add an accessible, user-controlled video section with desktop/mobile styling
• add prominent GitHub repository CTAs to the hero and film section
• add a clickable video preview and direct film link to the README
• add a current ready-to-post LinkedIn update to the launch kit
• record the now-live GitHub Marketplace listing and demo-video checklist items

Why

The README and product site had an animated terminal sample but not the supplied launch film, and the homepage's repository links were too easy to miss. This gives visitors a fast product story, a clear route to the source, and reusable launch copy grounded in the verified v0.6.2 release.

Validation

• npm run ci (119 tests plus typecheck, lint, production build, audit gate, Action/MCP checks, smokes, evaluation, and benchmark)
• desktop full-page visual verification
• 390px mobile full-page verification with no horizontal overflow
• video metadata reached ready state 4 and reported 23.6 seconds
• Next.js error-overlay check returned OK
• supplied and checked-in MP4 SHA-256 hashes match