agent-setup/prompt.md: Cursor skills install command fails with --global

Hi Cloudflare docs team — I followed the Cloudflare agent-setup instructions for Cursor, but the “other agents” install command wasn’t a turnkey experience for Cursor on my machine. It errored and required a manual workaround.

Here’s the exact failure and what I think the docs should change.

## Affected docs
- https://developers.cloudflare.com/agent-setup/prompt.md ("Install for other agents" section)
- Related Cursor guidance: https://developers.cloudflare.com/agent-setup/cursor/

## What I followed
From `prompt.md`, I ran the documented install command for other agents:

```sh
npx -y skills add cloudflare/skills --skill '*' --yes --global
```

## Actual behavior (Cursor)
On my machine, the command:
- copied skill files under `~/.agents/skills/*`
- but then failed/aborted the “global install” step with:

> `PromptScript: PromptScript does not support global skill installation`

As a result, the skills were **not available in Cursor's expected directory** (`~/.cursor/skills/*`). I had to manually copy the skill folders from `~/.agents/skills/` into `~/.cursor/skills/`.

## Why this is a docs problem
The doc command implies a turnkey install step for “other agents”, but for Cursor it requires a manual workaround.

## Suggested fix
Either:
1. Update `prompt.md` to use a Cursor-compatible install command (no `--global`, or the correct install destination), and/or
2. Add an explicit Cursor note explaining the expected target directory and what to do if `--global` is unsupported.

## Environment
- OS: Windows 10 (Win32)
- Tooling: Cursor Composer/agent