Add ClawSec and ClawSearch - AI agent skill security

[huacheng]

Summary

• Add ClawSec — security audit platform for AI agent skills with five-tier detection (core rules → dynamic rules → LLM analysis → Firecracker sandbox → LLM review), continuous rule evolution, and automated vulnerability reports.
• Add ClawSearch — AI agent skill discovery platform with trust scoring, pre-install security checks, and vulnerability assessment across 33k+ skills.

Both entries are added to the Code section in alphabetical order, matching the existing table format.