v3.15.0

Added

• RULES contract — dated, sourced, reasoned project rules (ADR-0039). The
  vault scaffold now creates RULES/TEMPLATE.md (es/en) and the managed rules
  block teaches the contract in its What-to-save section: keep project
  rules (knowledge invisible from the repo — domain contracts, deliberate
  traps, user mandates), each carrying its why (history), its source
  (the file/test/ADR that defines or enforces it) and a last_verified
  date; re-verify a rule against its source when you use it, and when a note
  contradicts the repo, fix the note in the same session. Grounded in an
  external multi-agent bench (sop-suite RUN1–RUN7): memory pays on invisible
  project rules, not on generic method (+2–3 pts/task); rules with a recorded
  why get respected; agents self-verify stale rules when the source of truth
  is one link away (aged-memory trap: 0/7 fell). Rules-block budgets raised
  es 8,400 → 9,100 / en 8,200 → 8,850 chars as a reviewed ADR-0036 decision
  (+~270 chars per language), with two new load-bearing phrases pinned per
  language.