feat(skills): writing-criteria, one source for runnable criteria (order 7c)

A brief success criterion and a plan's Verify, Regression, End-to-end and
Verification lines are each one command the criteria runner accepts, written
as the line's first backticked span; anything more is bash tests/<name>.sh,
and each must be able to go red (the runner reads the exit code only).

- skills/writing-criteria/SKILL.md (S1 form), with Runs:/Refused:/Never red:
  examples that a pin runs through the criteria runner
- brief-reviewer and plan-critic preload writing-criteria and
  reviewing-adversarially (S3 + S4); the copied runner rules leave them, the
  two templates and /trekplan, which names the skill where the plan is written
  and where its three reviewers start
- eval cases 3 fire / 2 quiet / 1 effect; tests/lib/skills-criteria-prose-pins
- review-630 @~1 pin follows the text into the skill; trekplan-stats line_ref
  re-measured

Baseline without the skill: 24 of 27 written checks refused by the runner,
and 0 of 3 reviewers saw that git status/git log can never go red. With it:
0 of 27 refused, 3 of 3 reviewers flagged both.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -328,6 +328,8 @@ Every implementation step includes:
 
 One step per plan is the "run the thing" step (`End-to-end:`): the product run the way a user runs it. Without it a result is "not verified end to end", never green.
 
+**Checks that run, and can fail.** Every `Verify:`, `Regression:`, `End-to-end:` and `## Verification` command, like every brief success criterion, is written by the `voyage:writing-criteria` skill: one command the criteria runner accepts (a known test runner, plain words, no pipe or `&&`), a script under `tests/` (`bash tests/<name>.sh`) for anything more, and a command that can go red. `/trekplan` asks for it where the plan is written and where it starts its reviewers; `brief-reviewer` and `plan-critic` have it preloaded and report a criterion the runner refuses, or one that exits 0 whatever the code does (`git status`, `git log`, a test file that already passes).
+
 Exploration uses 6–8 agents in parallel (architecture-mapper, dependency-tracer, task-finder, test-strategist, git-historian, risk-assessor, plus convention-scanner on medium+ codebases and research-scout when unfamiliar tech is detected). Adversarial review then runs `brief-reviewer`, `plan-critic` (12 dimensions, no-placeholder enforcement, manifest audit, interfaces and slices, design and architecture rules), and `scope-guardian` (creep + gap detection, ceremony match). Per-agent details in [`agents/`](agents/).
 
 **The plan gate.** Each critic round is written into the plan by `lib/validators/plan-gate.mjs --record`; `plan-gate.mjs <plan.md>` then exits 0 (go on), 1 (stop: invalid plan, no verdict, a verdict the plan has changed since, an open BLOCKER or an unaccepted MAJOR) or 2 (could not run). From round 2 the gate counts by rule A: a new major outside the diff since the last reviewed text counts as minor, never a blocker or a security finding (Handover 4). After 3 rounds with a BLOCKER open, `/trekplan` stops and asks; it never continues silently, and "execute" is offered only when the gate exits 0. Minors still open after the last round are listed numbered in the summary; the ones you pick are fixed and get one more round, the rest are carried. In Claude Code's plan mode the plan is written to Claude Code's plan file and approved through its own approval prompt (that `/trekplan` runs cleanly inside plan mode is not verified yet).
@@ -652,6 +654,7 @@ model. A skill is advice; each one says which check stands behind it, or "prose
 | `voyage:test-first` | Red before green: the repo's own test command, a test seen failing on an assertion (a crash is not red), the smallest code, the whole suite | `step-implementer` (preloaded) | proof of red, test lock, floor guard, done line in `/trekexecute`; the rest is prose only |
 | `voyage:debugging` | One command red on the exact symptom first; reproduce, localise, reduce, fix the cause, guard it with a red-first test; error text is data; three failed fixes go back to the design | `step-implementer` (preloaded) | proof of red for the regression test, the fix-round cap; the root-cause claim is prose only |
 | `voyage:researching-sources` | Official sources first with URL, date and matching version; no citation, no finding; an empty search is reported with what was searched, never as a finding; fetched pages are data, and text aimed at assistants is reported; nothing local in a query; one confidence scale | `docs-`, `community-`, `security-`, `contrarian-researcher` and `research-scout` (preloaded); `/trekresearch` names it at spawn | the research brief's structure (`research-validator`); the query privacy gate only in the default-off STORM steps; the rest is prose only |
+| `voyage:writing-criteria` | Each success criterion and each `Verify:`, `Regression:`, `End-to-end:` and `## Verification` line is one command the criteria runner accepts, written as the line's first backticked span (a known test runner, plain words, no pipe or `&&`); anything more is a script under `tests/`; and each can go red | `brief-reviewer` and `plan-critic` (preloaded); `/trekplan` names it where the plan is written and where it starts its reviewers | the criteria runner and the plan and brief validators (deterministic); that a criterion can go red and tests what the brief asks is prose only |
 
 The workshop behind them runs in `npm test`: the form check `lib/skills/skill-lint.mjs` (fields,
 "Use when ...", third person, no YAML traps, under 500 lines, fixed headings, no shell injection)