Skill-first rule now has two halves: route the request to a doing-skill,
then gate the result with the matching check-skill before 'done' --
inferred from the request, not user-named. Adds .claude/SKILL_ROUTING.md
(on-demand request->doing-skill->check-skill map). Enforcement tier A+B
(CORE rule + map; Stop-hook backstop deferred). Calibrate to stakes,
Ollama Tier-0 for cheap passes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>