v0.5.3

Three defects of one kind, all found by operating the reference tannery: a
configuration or prompt mistake that produced no error, only a run that looked
successful. Two are fixed by failing closed at load; the third replaces a prompt
sentence with a mechanism.

Added

• require_tool: — a turn that must act cannot end on text
  (#84).
  A turn whose job is to dispatch, file, or publish ends the moment the model
  produces text, and producing text instead of acting is the failure mode:
  observed, a fan-out agent composed five dispatch blocks as its reply, called
  nothing, and recorded success while zero downstream work was queued. The only
  defense was a sentence in the prompt, re-breakable by anyone who rewrote it.
  A turn header may now name required tools; a text response arriving with none
  of them called is refused, the model is told to make the call, and the turn
  continues. If the turn's tool rounds run out first the run fails, naming the
  turn and the tool. Any one named tool satisfies the requirement, and a call
  that fails counts — the requirement is that the model attempted the act. A
  requirement no tool in that turn's scope can satisfy is rejected by
  leather validate and again at run start, before the first LLM call.

Fixed

• An unrecognized turn header key is an error, not prompt text
  (#82).
  The turn parser recognized four keys and silently treated any other
  declaration-shaped line as the first line of the prompt. tool_rounds: 12 set
  no budget and shipped to the model as prose; a typo'd toolset: left the turn
  inheriting the previous turn's scope, which is the case where a turn written
  to drop a write tool keeps it. Both produced a clean run and no warning. A
  header-position line naming an unrecognized key now fails the load, naming the
  file, the turn, and the five recognized keys. The header also ends at the
  first blank line, so a prompt that genuinely opens with word: has somewhere
  to put it. Measured against every agent under examples/ and every agent
  block in docs/: no existing turn changes meaning.
• Lifecycle output: type: queue produced items no curing could consume
  (#83).
  The route enqueued an item carrying only a payload. A curing's first act is to
  load its item's hide, so every item this route produced hit "hide missing" and
  dead-lettered on first touch — there was no input for which it worked, and the
  schema accepted it, leather validate passed it, and the failure surfaced only
  as a growing DLQ. The route now writes the response to the hide store and
  enqueues a reference to it, matching what curing-to-curing chaining already
  did. Where no hide store is available the route warns and enqueues nothing
  rather than producing an item guaranteed to dead-letter.

Documentation

• docs/GUIDE.md gains the full turn-header key table, the require_tool
  contract, a shape-selection table for picking between cron, curing, fan-out
  and fan-in, five authoring anti-patterns drawn from live failures, and two
  corrections: hide_types does not filter chained artifacts (a chained hide
  carries the upstream curing's name as its kind), and page_size_bytes smaller
  than the document silently drops the tail an end-of-document guard depends on.