Audit and consolidate documentation in context architecture

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

Audited docs/ADRs/specs/lessons against context architecture: gate+selftest green, no stale/duplicate/history content found; advisories were false positives. No change needed. Memory: none applied.