Add more SOUL.md examples for different domains

[simonhsze]

What

Create example SOUL.md files for common agent roles beyond the current analyst/critic/judge set.

Suggested domains

• Code reviewer — reviews PRs with security and quality focus
• Product manager — evaluates feature requests with user impact scoring
• Risk analyst — assesses financial or operational risk
• Content moderator — flags policy violations with confidence levels

How

1. Create a new directory under examples/agents/{domain}/
2. Write a SOUL.md with Mission, Hard Constraints, and Personality sections
3. Follow the pattern in examples/agents/analyst/SOUL.md
4. Bonus: add a demo script showing the agent in action

Why this matters

Good SOUL.md examples help new users understand how to write their own constitutions. The more domains covered, the more people see themselves using this.