StyleLatch v0.3.0

Added

• A fourth layer, and the first one that reads rather than writes. A style
  may declare machine-checkable assertions in its frontmatter, and a Stop
  hook measures the finished reply against them:

  checks: max_sentence_words=25; forbid=let me know if; no_bullets

  Rules: max_sentence_words, max_reply_lines, max_reply_chars,
  max_paragraphs, forbid, forbid_opening, require, no_headings,
  no_bullets. Modifiers can add checks, and they accumulate.

• Closed-loop correction. Breaking a check puts one short line in the next
  turn's nudge naming the rule that broke, instead of restating the whole
  style. Naming the specific failure is a stronger signal for fewer tokens.
  Each breach is delivered exactly once, so a host without a Stop hook cannot
  nag forever about one old reply.

• ::status reports adherence over the recent replies, and what broke.

• ::test fails on a checks line it cannot parse. A check that is silently
  never enforced is the worst outcome: the style looks measured and is not.

• The five built-in styles that have mechanically checkable rules now declare
  them, so this works without writing a style first.

• One-shot latches: ::terse! explain this regex applies the rules to that
  message and latches nothing, so trying a style — or asking for one plain
  answer — no longer costs you the style you actually work in.

• A bounded record of what was latched and when. ::status shows the last
  five, so "what did I switch away from" is answerable.