docs drift: lifecycle hooks, plans vs specs location, superseded specs #602

1. docs/framework/lifecycle.md never mentions register_setup_steps (and lists fewer hooks than ModuleBase has). Add it and a test asserting every register_* on ModuleBase appears in the doc.
2. Design docs live in two places: docs/plans/ (10 files, newest 2026-10-15) and docs/superpowers/{plans,specs} (27 + 38, all recent work). CLAUDE.md says "docs/plans/ — the newest is the intended state", pointing at the stale one. Pick one directory, add a status: header (current/superseded/implemented), update CLAUDE.md.
3. Old April plans (e.g. 2026-04-13-alembic-migrations.md) predate the multi-root/multi-head migration history; mark superseded.
4. docs/testing/* / CLAUDE.md: re-check wording on the Postgres suite after Speed up the Python test suites: per-worker Postgres DBs, schema reuse, lazy route resolution #577 (now parallel with per-worker DBs).

From the Oct 2026 tech-debt survey of main@1c4270ac.