ci: specs live in the issue body — body digest in review anchors, gate without a spec file

The spec file solved exactly one problem — proving that a review verdict
was passed on a given text — and created two: docs/specs/README.md
conflicted between parallel tasks and served as a second, stale status
dictionary, and every spec edit cost a commit, a push and a label. The
proof moves into the pipeline.

- review-doc-guard: normalizeIssueBody / issueBodyDigest (CRLF, trailing
  whitespace, trailing newlines), the anchor line `Тело issue: <sha256>`,
  anchorIssueBodyFrom, and issueBodyChanged — the finding "the spec
  changed after a green spec review", judged against the pipeline's own
  record in the last green SPEC-REVIEW, never against prose.
- reusableGreenVerdict takes the current digest: reuse (#499) skips the
  model entirely, so without this a spec edit between rounds would pass
  unseen. Documents without the record (the whole backlog) keep judging
  by tree.
- process.yml: the material step reads the body with `gh issue view` in
  the same run that fixes the material — the event snapshot describes a
  text the reviewer may never see; the digest goes into the anchors, into
  reuse and, when it differs, into the reviewer's prompt.
- process-gate: rule 3 judges the text (a `## ТЗ` heading or an AC1) with
  the archived file still accepted; adding a new file under docs/specs/
  warns — the directory is frozen.
- task-packet reads AC from the body first, the archived file second.
- PROCESS.md §2.3/§5/§7.1/§7.3/§10.5, AGENTS.md and docs/specs/README.md
  say so; the index table is gone with the long-standing §7.3 debt.

Mutants: review-anchor-drops-issue-body, review-ignores-changed-spec-body,
reuse-ignores-changed-issue-body, process-gate-requires-spec-file.

Issue: #517
User-Visible: no

scripts/mutation-gate.mjs

@@ -8192,6 +8192,50 @@ const MUTANT_DEFINITIONS = [
       replace: "        // mutant: completed means green — a red dispatch falls through to the job check",
     }],
   },
+  {
+    id: 'review-anchor-drops-issue-body',
+    guard: 'node --test test/review-doc-guard.test.mjs',
+    because: 'ТЗ живёт в теле issue, которое GitHub правит без diff и без истории: без хеша тела '
+      + 'в якорях доказать «вердикт вынесен на этом тексте» нечем (#517 AC1)',
+    patches: [{
+      file: 'scripts/review-doc-guard.mjs',
+      find: '    lines.push(`- Тело issue: \\`${issueBody}\\``);',
+      replace: '    // mutant: anchor without the issue body',
+    }],
+  },
+  {
+    id: 'review-ignores-changed-spec-body',
+    guard: 'node --test test/review-doc-guard.test.mjs',
+    because: 'правка ТЗ после зелёного ревью ТЗ обязана приходить ревьюеру кода находкой; '
+      + 'сравнение, которое всегда молчит, возвращает ровно ту слепоту, ради которой заведён хеш (#517 AC2)',
+    patches: [{
+      file: 'scripts/review-doc-guard.mjs',
+      find: '  return recorded === digest ? null : { doc: green.name, recorded, current: digest };',
+      replace: '  return null; // mutant: the body never changed',
+    }],
+  },
+  {
+    id: 'reuse-ignores-changed-issue-body',
+    guard: 'node --test test/review-doc-guard.test.mjs',
+    because: 'повторное применение зелёного вердикта пропускает вызов модели целиком: если оно не '
+      + 'смотрит на хеш тела, правка ТЗ между раундами проходит невидимой (#517 AC6)',
+    patches: [{
+      file: 'scripts/review-doc-guard.mjs',
+      find: '  if (recordedBody && issueBodyDigest && recordedBody !== issueBodyDigest) return null;',
+      replace: '  // mutant: reuse ignores the issue body',
+    }],
+  },
+  {
+    id: 'process-gate-requires-spec-file',
+    guard: 'node --test test/process-gate.test.mjs',
+    because: 'после #517 файла ТЗ не создаёт ни одна новая задача: гейт, требующий файл, краснеет '
+      + 'на каждом классе A и учит игнорировать себя (#517 AC3)',
+    patches: [{
+      file: 'scripts/process-gate.mjs',
+      find: '      if (hasSpecText(body)) continue;',
+      replace: '      if (body !== null) continue; // mutant: only the file counts',
+    }],
+  },
   {
     id: 'review-returns-task-on-cancelled-dispatch',
     guard: 'node --test test/validate-gate.test.mjs',