v0.4.0

Changed

• Docs aligned to the 9-verb agent-facing MCP surface (the-librarian
  ADR 0006). The agent-facing surface is now recall, remember,
  flag_memory, store_handoff, list_handoffs, claim_handoff,
  list_skills, get_skill, search_references (plus the internal
  conv_state_* primer). README, SPEC, and the /toggle-private command
  doc no longer reference the retired verbs: verify_memory is replaced
  by flag_memory (flag a wrong/misleading/outdated memory; routed to
  review), propose_memory is folded into remember, the per-turn
  conv_state_get primer covers what start_context used to, and
  session_manifest / find_skills are replaced by list_skills. The
  README now also documents the list_skills / get_skill /
  search_references skill + reference tools. Docs-only — no runtime or
  API change.