Add Kiro to README Supported Tools table

[avifenesh]

Summary

Kiro is absent from the README's Supported Tools table despite having 5 implemented rules and 22 more planned.

Current table (README.md:112-123)

Lists: Agent Skills, Claude Code, GitHub Copilot, Cursor, MCP, AGENTS.md, Gemini CLI. Kiro is missing.

What's needed

Add Kiro row to the table. After all rules are implemented:

| [Kiro](https://kiro.dev) | KIRO-\*, KR-\* | 27 | .kiro/steering/\*.md, .kiro/hooks/\*.kiro.hook, .kiro/agents/\*.json, POWER.md, .kiro/settings/mcp.json |

Initial entry (current state):

| [Kiro](https://kiro.dev) | KIRO-\*, KR-SK-\* | 5 | .kiro/steering/\*.md |

Acceptance criteria

• Kiro row added to Supported Tools table in README.md
• Rule count and config files accurate for current state