v0.9.0 — state consistency wave

All run.toml writers now go through the flock'd transaction (unlocked helpers are test-only, compile-enforced) (#28); stuck-pending adoptee recovery — checkpointed, idempotent, never re-launches into a live pane (#29); manifest relink procedure documented (#16); codex prompting skill incl. $-skill invocation discovery (#34). 159 tests.