Lead the README with a walkthrough clip and link GitHub from the app

[valuecodes]

What

• The README showed only a still screenshot, but movement is what explains the project. The hero shot stays, and a 12 s looping clip now sits directly under it: the world map pulls out from one file to this whole repository, then a walk through the demo goes into main(), its if (user) fork room and the getUser() call door.
• The clip is an animated WebP (2.2 MB) with no captions. It was captured frame by frame in headless Chromium on a virtual clock, so motion is smooth despite software WebGL. The capture scripts stay outside the repo.
• The app had no link back to its source. A GitHub button now sits under the key list on the landing page and on the "Click to start walking" screen. Clicking it doesn't lock the pointer, and it stays clickable while a repository is being read.

How to test

pnpm install
pnpm dev
pnpm test

Open http://localhost:3000/ and http://localhost:3000/?code=self: the GitHub button is under the key list. Clicking it opens the repo in a new tab without starting to walk.

Security review

No security-impacting changes.

🤖 Generated with Claude Code

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-14T13:06:25.210817Z	31eba8c	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.