Add Claude Code guide

[ethanpalm]

Documentation changes

This PR adds a guide on using Claude Code to maintain your docs. It includes a sample CLAUDE.md file, prompts for people to quickly get value from Claude Code, and ideas to inspire people to integrate it more deeply into their docs workflows without just reproducing Anthropic's docs.

Closes https://linear.app/mintlify/issue/DOC-90/add-claudemd-example

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For Reviewers

When reviewing documentation PRs, please consider:

✅ Technical accuracy

• Code examples work as written
• Commands and configurations are correct
• Links resolve to the right destinations
• Prerequisites and requirements are accurate

✅ Clarity and completeness

• Instructions are clear and easy to follow
• Steps are in logical order
• Nothing important is missing
• Examples help illustrate the concepts

✅ User experience

• A new user could follow these docs successfully
• Common gotchas or edge cases are addressed
• Error messages or troubleshooting guidance is helpful