AgentCAD 0.1.0: double-click installer

First release with a double-click installer. No terminal needed.

Windows: download AgentCAD-Setup.cmd and double-click it. If Windows says "Windows protected your PC", click More info, then Run anyway.

macOS / Linux: download AgentCAD-Setup-mac.zip, double-click it to unpack, then open AgentCAD-Setup.command. If macOS says it cannot check the developer, right-click the file and choose Open.

What happens:

1. A small window with a progress bar downloads what is needed. The first time takes about a minute.
2. A setup page opens in your browser, in English or Chinese. Apps found on your computer (Claude Code, Codex, Claude Desktop, Cursor) are already ticked. Tap Install now and each step gets a green tick.
3. An AgentCAD icon on your desktop opens your drawings any time. The last page gives sentences to copy to your assistant.

Already installed? Run the installer again and tap Already installed? Check it.

The installer always fetches the latest AgentCAD from main. The files are not code-signed yet. Details: docs/install.md.