Consolidate and clean outdated documentation

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 all docs (ADRs, policies, integrations, portfolio, reader docs): found them already clean; fixed one stale apps/mobile ref. Quick gate green; PR #7193 queued to merge lane. Deferred: deep prose pass on very large docs.