Add structured Code Agent blocker taxonomy across /v1/agent/chat, runner/session/tool, and HWLAB M3 Skill CLI paths.\n\nValidated with npm run check and focused server/session/Skill CLI/web tests.
Adds the Code Agent -> Skill CLI -> HWLAB API /v1/m3/io controlled M3 IO path with route/audit/evidence/blocker payloads and tests proving no direct gateway/box/patch-panel or OpenAI fallback hardware control.