chore(scripts): witness the generated copies of the 12966/4997 measurement sentence in check:future-spec-major

From protocol 18 on, gen:spec-changes projects step 18's semantic entries into
the per-major 17 -> 18 record and the aggregate record (spec-changes.json, two
copies) and gen:upgrade-guide renders them into the Protocol 17 -> 18 section
(protocol-upgrade-guide.md, one copy). The registry.ts measurement entry's
evidence sentence travels with them, so its "@objectstack/spec 4997" count is
quoted three more times. Two kind 'measurement' ledger entries with the same
witness regex and exact covers counts; the matcher, the path scope and the
recorded rationale are unchanged.

Claude-Session: https://claude.ai/code/session_01LAi5BVvQNiYzepSAcsoFLK
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

scripts/check-future-spec-major.mjs

@@ -347,6 +347,29 @@ const QUOTATION_EXEMPTIONS = Object.freeze([
       'The same recorded evidence sentence, in the registry that carries the '
       + 'semantic entry above. A count, not a version.',
   },
+  {
+    file: 'packages/spec/spec-changes.json',
+    major: 4997,
+    kind: 'measurement',
+    covers: 2,
+    witness: /controls objectstack 12966 and @objectstack\/spec 4997 on the same corpus/,
+    why:
+      'The generated copies of that same semantic entry\'s evidence sentence: '
+      + '`gen:spec-changes` projects step 18\'s semantic entries into the '
+      + 'per-major 17 → 18 record and into the aggregate record, once each, '
+      + 'from protocol 18 on. A count, not a version.',
+  },
+  {
+    file: 'docs/protocol-upgrade-guide.md',
+    major: 4997,
+    kind: 'measurement',
+    covers: 1,
+    witness: /controls objectstack 12966 and @objectstack\/spec 4997 on the same corpus/,
+    why:
+      'The generated copy of that same semantic entry\'s evidence sentence: '
+      + '`gen:upgrade-guide` renders step 18\'s semantic entries into the '
+      + 'Protocol 17 → 18 section from protocol 18 on. A count, not a version.',
+  },
   {
     file: 'docs/adr/0021-analytics-dataset-semantic-layer.md',
     major: 6526,