npx ENOTEMPTY error on macOS when running @claude-flow/cli

## Problem

Users on macOS encounter an `ENOTEMPTY` error when running npx commands:

```
npm error code ENOTEMPTY
npm error syscall rename
npm error path /Users/.../.npm/_npx/.../node_modules/@claude-flow/cli
npm error dest /Users/.../.npm/_npx/.../node_modules/@claude-flow/.cli-YMjh8UPt
npm error errno -66
npm error ENOTEMPTY: directory not empty, rename '...'
```

## Cause

This is an npm cache corruption issue, not a claude-flow bug. It occurs when:
1. npx cache becomes corrupted during interrupted installs
2. npm tries to rename directories that aren't empty
3. File system race conditions on macOS

## Solution

Clear the npx cache:

```bash
# Remove the corrupted npx cache
rm -rf ~/.npm/_npx

# Then retry
npx @claude-flow/cli@latest --help
```

## Prevention

If this happens frequently:
```bash
# Use npm cache clean
npm cache clean --force

# Or install globally instead of using npx
npm install -g @claude-flow/cli
claude-flow --help
```

## Environment
- OS: macOS
- npm version: Various
- Node version: Various

## Labels
- documentation
- not-a-bug
- user-environment

No repository file or test is named in the issue. Start by locating the documentation for running @claude-flow/cli with npx, then compare its macOS ENOTEMPTY troubleshooting guidance with the commands and prevention steps described here; done means the relevant documentation clearly explains cache cleanup and retry options.

Written by the indexing model from the issue text.