v0.15.0 — no size limit for project memory; multi paths, --grep AND, --project OR

• No size limit for project memory: sessions beyond the per-note
  budget are now map-reduced inside the note (chunk notes on turn
  boundaries + one synthesis, all cached) — the brief inherits the
  same nothing-silently-dropped guarantee as --llm, at any size.
• Multi params: chf a.jsonl b.jsonl … merges several sessions
  into one handoff; --grep X --grep Y requires ALL terms (AND);
  --project A --project B searches several projects together.
• Docs: new docs/GUIDE.md (day-with-it walkthrough, --brief
  step-by-step, honest cost table, cheatsheet); a second demo GIF shows
  project memory end-to-end; brief/Using latest session messages print
  ~-collapsed paths.