fix: brief template teaches runnable criteria; commands call validators through the plugin root

The skills reading (2026-10-06) found two defects the operator decided to fix
once wave 1 was merged:
- the brief template's Success Criteria examples used a pipe and npx, which
  the criteria runner refuses (and the brief validator now warns on);
- trekcontinue and trekexecute called lib/ scripts relative to the working
  directory, which is the user's repo, not the plugin.

Tests fail on the old text first (tests/lib/reading-defects.test.mjs).

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

tests/lib/reading-defects.test.mjs

@@ -0,0 +1,42 @@
+// tests/lib/reading-defects.test.mjs
+// Defects the skills reading found (docs/skillsanalyse.local.md § 6, 2026-10-06);
+// the operator decided they are fixed in a small delivery once wave 1 was
+// merged. Each test fails on the code the reading measured.
+
+import { test } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { readFileSync, readdirSync } from 'node:fs';
+import { dirname, join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { runnableCheck } from '../../lib/verification/criteria-runner.mjs';
+
+const HERE = dirname(fileURLToPath(import.meta.url));
+const ROOT = join(HERE, '..', '..');
+const read = (p) => readFileSync(join(ROOT, p), 'utf8');
+
+// --- 1. the brief template teaches only criteria the runner can run ---------
+
+test('brief template: every example command under Success Criteria is one the criteria runner accepts', () => {
+  const md = read('templates/trekbrief-template.md');
+  const start = md.indexOf('## Success Criteria');
+  const section = md.slice(start, md.indexOf('\n## ', start + 1));
+  const examples = section.split('\n').filter((l) => l.startsWith('- {criterion')).join('\n');
+  const commands = [...examples.matchAll(/`([^`\n]+)`/g)].map((m) => m[1]).filter((c) => !/^"/.test(c));
+  assert.ok(commands.length >= 3, `found ${commands.length} example commands`);
+  for (const command of commands) {
+    const r = runnableCheck({ command });
+    assert.equal(r.runnable, true, `${command}: ${r.reason}`);
+  }
+});
+
+// --- 2. commands reach Voyage's own scripts through the plugin root ---------
+
+test('commands: no Voyage script is called relative to the working directory (it is the user\'s repo)', () => {
+  const offenders = [];
+  for (const f of readdirSync(join(ROOT, 'commands')).filter((n) => n.endsWith('.md'))) {
+    read(`commands/${f}`).split('\n').forEach((line, i) => {
+      if (/(?:node |from ['"]|import\(['"])(?:\.\/)?lib\//.test(line)) offenders.push(`commands/${f}:${i + 1}`);
+    });
+  }
+  assert.deepEqual(offenders, []);
+});