Explain idle vs mid-turn delivery with pi-auto-compact and how to use
debug snapshots when last compaction shows none incorrectly.
Co-authored-by: Cursor <cursoragent@cursor.com>
Document implemented status, pi -e installation, /skill-reinject usage,
and coexistence guidance per SPEC §9.1 and §16.7.
Co-authored-by: Cursor <cursoragent@cursor.com>