Clean Up Stale Documentation Via CLAUDE.md

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 merged (PR #4955): 3 ADRs merged into homes, ADRs trimmed, history/task ids/stale refs removed. CI gate + deploy green; local full stopped at compose-stack port. Deferred: ADR-0025/0048 merges, lessons deletions.