Polish grant-ready docs and demo

[horn111]

Description

Grant-ready polish pass for arc-nano-kit.

This update packages the project for Arc/Circle grant review: clearer README positioning, a dedicated grant snapshot, a reproducible demo script, updated architecture/docs, and a polished local demo surface that shows the full Arc Receipts ops flow.

Flow covered:

• create invoice
• build memo payment request
• watcher generates receipt
• signed webhook delivered
• local inbox verifies signature
• replay creates delivery attempt Add Arc Testnet receipt watcher #2

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Refactoring

Related Issues

Closes #

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have added tests that prove my fix/feature works
• New and existing tests pass locally with my changes
• I have updated the documentation accordingly
• I have updated the CHANGELOG.md

Testing

• node_modules\.bin\tsc.cmd --noEmit --project apps/demo/tsconfig.json --incremental false
• git diff --check
• npm.cmd run test --workspaces --if-present -- --reporter=dot
• npm.cmd run build in apps/demo
• Local demo checked on http://localhost:3005

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
arc-nano-kit-demo	Ready	Preview, Comment	Jul 1, 2026 11:11am