feat(site): showcase real gameplay video

[Codewriter90x]

Summary

Adds a polished 42-second real gameplay tour to the public project presentation.

• publishes the canonical video on YouTube;
• embeds it on the Italian and English website through youtube-nocookie.com;
• adds a clickable poster and call to action to the README;
• records the poster in the asset provenance manifest;
• extends provenance coverage to common video formats.

Tour

Menu → guided kit setup → lesson selection → countdown → gameplay.

The capture uses only first-party HitTheKit interfaces and synthetic gameplay. The instrumental soundtrack was created specifically for this video and contains no commercial recording, chart, artwork, or performer likeness.

Watch: https://youtu.be/10wJjOFGMCg

Validation

• website localization contracts: pass (it, en)
• asset provenance contracts: pass (66 tracked assets)
• public readiness contracts: pass (0.5.0, public)
• desktop browser smoke: pass
• mobile 390×844 responsive smoke: pass
• English route and privacy-enhanced embed: pass
• YouTube copyright checks: no issues found

Scope

Website, README, and public documentation only. No Unity binaries or commercial content are added.