test(r8): move the live tests out of the round files

R8 of cleanup R-a (plan .claude/projects/2026-11-07-cleanup-r-a, appendix A).
The live tests of the round files move into the test named after their
source; each moved test was seen red under a mutation of its source.
New: tests/lib/lib-imports.test.mjs, tests/lib/timing.test.mjs (from
timing-under-load). The [#1] --gates rule and shim-line pins move into
tests/lib/autonomy-gate.test.mjs.

Removed: the round test files (retterunde, retterunde-prose-pins,
trial-mechanical-fixes, trial2-fixes, trial2-minor, trial2-minor-prose-pins,
fix-round-4-5a-prose, fix-round-4-5b2-b-prose, timing-under-load), the 8 R8
e2e scripts, and seven round test files on the R-a removal list that pinned
them (fix-round-4-5b-prose, fix-round-4-5b-part-2/3/4-scripts,
fix-round-4-5b-part-4-prose, fix-round-4-5b2-b/c-scripts). The diff-mode e2e
pin (test 24) and the red-script round-wrapper cases go too.

tests/synthetic/plan-run-C.md becomes tests/fixtures/plan-run-c.md,
regenerated from buildPlan({ version: '1.9' }). The red judge, reporter and
judge test headers now name the shared red script.

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

tests/validators/plan-validator.test.mjs

@@ -1,6 +1,8 @@
 import { test } from 'node:test';
 import { strict as assert } from 'node:assert';
 import { validatePlanContent } from '../../lib/validators/plan-validator.mjs';
+import { ON_FAILURE_ACTIONS } from '../../lib/parsers/plan-schema.mjs';
+import { buildPlan } from '../helpers/plan-v18-builder.mjs';
 
 const VALID_PLAN = `---
 plan_version: "1.7"
@@ -111,3 +113,87 @@ test('validatePlan — prose plan_version line parses, no PLAN_NO_VERSION (defec
   assert.equal(r.parsed.planVersion, '1.7');
   assert.equal(r.warnings.find(w => w.code === 'PLAN_NO_VERSION'), undefined);
 });
+
+const codes = (list) => list.map((e) => e.code);
+
+// ---- PLAN_STEP_TESTS_ONLY: a step whose Files are all tests can never be proven red ----
+
+// Step 2 changes only tests for behaviour step 1 delivered.
+const TESTS_ONLY_PLAN = buildPlan({
+  steps: [{}, { file: 'tests/e2e.sh', test: 'tests/e2e-guard.test.mjs', endToEnd: 'bash tests/e2e.sh' }],
+});
+
+test('a step whose Files are all tests gives PLAN_STEP_TESTS_ONLY, a warning on that step', () => {
+  const r = validatePlanContent(TESTS_ONLY_PLAN);
+  const w = r.warnings.filter((x) => x.code === 'PLAN_STEP_TESTS_ONLY');
+  assert.equal(w.length, 1, codes(r.warnings).join(','));
+  assert.match(w[0].message, /Step 2/);
+  assert.ok(!codes(r.errors).includes('PLAN_STEP_TESTS_ONLY'), 'a warning, never an error');
+  assert.equal(r.valid, true, codes(r.errors).join(','));
+});
+
+test('a step with code and its test gives no PLAN_STEP_TESTS_ONLY', () => {
+  const r = validatePlanContent(buildPlan());
+  assert.ok(!codes(r.warnings).includes('PLAN_STEP_TESTS_ONLY'), codes(r.warnings).join(','));
+});
+
+// ---- K10 `Regression:` and K11 `On failure:` -----------------------------------
+
+// Step 1's Verify line in the builder's plan; the new field goes right under it.
+const STEP1_VERIFY = '- **Verify:** `node --test tests/mod1.test.mjs` → expected: pass';
+const withRegression = (line, plan = buildPlan()) => plan.replace(STEP1_VERIFY, `${STEP1_VERIFY}\n${line}`);
+const withOnFailure = (text, plan = buildPlan()) =>
+  plan.replace(/^- \*\*On failure:\*\* .*$/m, `- **On failure:** ${text}`);
+
+test('K10: `Regression: npm test | tee x` is refused — one command, unpiped', () => {
+  const r = validatePlanContent(withRegression('- **Regression:** `npm test | tee x` → expected: exit 0'));
+  assert.equal(r.valid, false);
+  const e = r.errors.find((x) => x.code === 'PLAN_STEP_REGRESSION_NOT_RUNNABLE');
+  assert.ok(e, codes(r.errors).join(','));
+  assert.match(e.message, /Step 1/);
+  assert.match(e.message, /shell operator/);
+});
+
+test('K10: `Regression: npm test` is accepted', () => {
+  const r = validatePlanContent(withRegression('- **Regression:** `npm test` → expected: exit 0'));
+  assert.deepEqual(codes(r.errors), []);
+  assert.ok(!codes(r.warnings).includes('PLAN_STEP_REGRESSION_NOT_RUNNABLE'));
+});
+
+test('K10: without the field the plan validates exactly as before', () => {
+  const r = validatePlanContent(buildPlan());
+  assert.equal(r.valid, true, codes(r.errors).join(','));
+  assert.deepEqual(codes(r.warnings), []);
+});
+
+test('K10: `npm test && bash tests/e2e.sh`, a bare word, or no backticks is refused', () => {
+  for (const line of [
+    '- **Regression:** `npm test && bash tests/e2e.sh`',
+    '- **Regression:** `./run-all-tests`',
+    '- **Regression:** npm test',
+    '- **Regression:**',
+  ]) {
+    const r = validatePlanContent(withRegression(line));
+    assert.ok(codes(r.errors).includes('PLAN_STEP_REGRESSION_NOT_RUNNABLE'), `${line}: ${codes(r.errors).join(',')}`);
+  }
+});
+
+test('K10: --soft reports an unrunnable Regression as a warning, not an error', () => {
+  const r = validatePlanContent(withRegression('- **Regression:** `npm test | tee x`'), { strict: false });
+  assert.equal(r.valid, true, codes(r.errors).join(','));
+  assert.ok(codes(r.warnings).includes('PLAN_STEP_REGRESSION_NOT_RUNNABLE'));
+});
+
+test('K11: `On failure: try again` warns, and the plan stays valid', () => {
+  const r = validatePlanContent(withOnFailure('try again'));
+  assert.equal(r.valid, true, codes(r.errors).join(','));
+  const w = r.warnings.find((x) => x.code === 'PLAN_STEP_ON_FAILURE_UNKNOWN');
+  assert.ok(w, codes(r.warnings).join(','));
+  assert.match(w.message, /Step 1/);
+  for (const word of ON_FAILURE_ACTIONS) assert.match(w.hint, new RegExp(word));
+});
+
+test('K11: `On failure: retry once, then escalate` gives no warning', () => {
+  const r = validatePlanContent(withOnFailure('retry once, then escalate'));
+  assert.ok(!codes(r.warnings).includes('PLAN_STEP_ON_FAILURE_UNKNOWN'), codes(r.warnings).join(','));
+});