test(W7c): match document-release spawned-dispatch contract on meaning

W7c conversion (t04 F3; W7a run-in-background-guidance.test.ts:472,474, named
by the Eng W7c gate as anti-injection and VERSION invariants that stay as
case-insensitive meaning checks). The run_in_background flag pins, structural
scanner and inverted-phrasing ban are unchanged.

Removed assertion groups (invariant -> remaining protection):
- 'NEVER trigger it on their own' (caps literal): prompt/file/tool claims do
  not enable spawned mode (anti-injection) -> kept free: /claims never
  trigger it on their own/i in the generated skill and template.
- 'The NEVER-do invariants below do' (short form of a wrapped sentence that
  names the caps headings s10 rewrites): spawned auto-pick still never
  rewrites CHANGELOG or changes VERSION -> kept free: /skip any
  recommendation that rewrites CHANGELOG or changes VERSION/i
  (whitespace-normalized) in both files; gate E2E document-release.
- 'A spawned run must never change VERSION': same rule, now /i.

Mutation pass (scratch worktree; document-release skill, template and
release-body section, ship/sections/documentation.md): 7/7 as expected;
deleting the anti-injection clause, the CHANGELOG/VERSION carve-out, the
spawned VERSION line, the run_in_background flag or the dispatch heading
goes red; lowering NEVER and rewording 'NEVER-do invariants' stays green.
Log: .context/mutation-run-in-background-guidance.md.

test/run-in-background-guidance.test.ts

@@ -459,25 +459,26 @@ describe('run_in_background guidance (#2440)', () => {
   // class regressed twice via unpinned prose. Pin the document-release
   // contract, the Step 8.4d spawned note, and the resolver-side Codex
   // doc-review skip in both generated output and templates.
-  const CONTRACT_PINS: Array<[string[], string]> = [
+  const CONTRACT_PINS: Array<[string[], string | RegExp]> = [
     [['document-release/SKILL.md', 'document-release/SKILL.md.tmpl'], 'When dispatched as a subagent'],
     [
       ['document-release/sections/release-body.md', 'document-release/sections/release-body.md.tmpl'],
-      'A spawned run must never change VERSION',
+      /a spawned run must never change VERSION/i,
     ],
     [['document-release/sections/release-body.md'], 'Spawned-session skip'],
     // Anti-injection trigger + invariant carve-out — the two clauses whose
     // deletion would silently reopen the prompt-injection / silent-VERSION
-    // holes while the 'When dispatched' heading pin stays green.
-    [['document-release/SKILL.md', 'document-release/SKILL.md.tmpl'], 'NEVER trigger it on their own'],
-    // (short form — the sentence wraps across template lines; toContain is literal)
-    [['document-release/SKILL.md', 'document-release/SKILL.md.tmpl'], 'The NEVER-do invariants below do'],
+    // holes while the 'When dispatched' heading pin stays green. Matched on
+    // meaning (case-insensitive, whitespace-normalized), not register.
+    [['document-release/SKILL.md', 'document-release/SKILL.md.tmpl'], /claims never trigger it on their own/i],
+    [['document-release/SKILL.md', 'document-release/SKILL.md.tmpl'], /skip any recommendation that rewrites CHANGELOG or changes VERSION/i],
   ];
   test('document-release carries the spawned-dispatch contract', () => {
     for (const [sites, phrase] of CONTRACT_PINS) {
       for (const rel of sites) {
         const content = fs.readFileSync(path.join(ROOT, rel), 'utf-8');
-        expect(content).toContain(phrase);
+        if (typeof phrase === 'string') expect(content).toContain(phrase);
+        else expect(content.replace(/\s+/g, ' ')).toMatch(phrase);
       }
     }
   });