chore: ruff format after mypy fixes

Add mcp-taxonomy adapter module

Add Nova-Rules patterns: malware keywords, policy puppetry, Claude triggers, scareware, weaponized code (10 categories total)

Add Steganographic Detection Engine: 4 new detectors (unicode_adv, stego_markers, entropy, image_stego) + tests + fixtures

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