Clean and consolidate old documentation into CLAUDE.md router

Use context architecture skill to scrub all old documentation, including instructions, specs, trackers, ADRs - delete everything superseeded and stale, remove references to historical decisions, delete duplicates, single home everything and make sure all documentation is accessible from CLAUDE.md router in a few steps

Docs scrub found nothing stale: gate green, no trackers or active specs, ADRs current (no dangling/missing citations), no duplicate prose, every doc ≤2 hops from router. No PR needed. Memory: none applied.