chore: ruff format after mypy fixes

Add mcp-taxonomy adapter module

Security hardening: SSRF validation, XSS escapes, rate limiting, proxy default 127.0.0.1, path traversal, webhook validation, security headers

Extend Red Team Lab with steganographic embedding methods (bidi, zalgo, stego markers, base64, hex, image LSB)

Initial release: Palisade Scanner v0.1.0 — web content security for AI agents