[phaethix]

Summary

Desktop users can optionally sign in to GitHub with the OAuth Device Flow and push or pull the open mind map as text in a secret Gist. ~/Documents/Mind stays the source of truth. Nothing is uploaded until the user confirms a push. The browser build has no sync commands.

Closes #21

Type of change

• Bug fix
• New feature
• Build, CI or tooling
• Documentation

How it was tested

• cargo test --locked --manifest-path desktop/src-tauri/Cargo.toml --lib github (device-flow mock, secret gist create/update, 1 MB limit, token file mode, link rename/delete, pull overwrite predicate)
• cargo check --locked --manifest-path desktop/src-tauri/Cargo.toml
• cargo fmt --manifest-path desktop/src-tauri/Cargo.toml --check
• bun x prettier --check .
• bun web/src/utils/fileLibrary.test.cjs, bun web/src/utils/mermaidMindmap.test.cjs, bun simple-mind-map/test/xmind-associative-line.test.cjs
• cd web && npm run build

The Tauri window was not launched here, so the menu, dialog, and a live GitHub device-code login were not clicked through.

Configure the OAuth App

1. Create an OAuth App at https://github.com/settings/developers. Homepage URL can be this repository. Device Flow does not use the callback; http://127.0.0.1 satisfies the form.
2. Enable Device Flow on the app. Copy the Client ID. Do not put a client secret in the app, the repo, or CI.
3. Provide the Client ID with MIND_GITHUB_CLIENT_ID at runtime or compile time, or as clientId in github.json next to ai.json. YOUR_CLIENT_ID in the README is a placeholder, not a real id.
4. Apply for the GitHub Developer Program at https://github.com/developer/register with a support email you monitor. This change does not submit that application.

Checklist

• I ran the relevant build or test locally — CI covers formatting and the web build
• Behaviour changes are reflected in the README or in code comments