test(red-proof): the two regression guards that pass at be0b631 get their own mutation ids

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

tests/fix-round-4-5b-mutations.mjs

@@ -234,4 +234,28 @@ run_tagged "$TMP/base.jsonl" --test-timeout=300000 --test-force-exit $PATS`,
       },
     ],
   },
+  {
+    key: 'M7r',
+    id: 'M7r',
+    what: 'a HEAD read that fails (exit 128, as on an unborn HEAD) counts as in HEAD, so nothing is parked',
+    spans: [
+      {
+        file: 'lib/util/park-attempt-files.mjs',
+        find: 'return r.status === 0;',
+        replace: 'return r.status === 0 || r.status === 128;',
+      },
+    ],
+  },
+  {
+    key: 'DJ4r',
+    id: 'DJ4r',
+    what: 'the lesson write returns when the lessons directory is missing, so the first lesson is never written',
+    spans: [
+      {
+        file: 'lib/review/recurrence.mjs',
+        find: 'mkdirSync(dirname(path), { recursive: true });',
+        replace: 'if (!existsSync(dirname(path))) return;',
+      },
+    ],
+  },
 ];