[baozhoutao]

Closes #15291

What changed

check-skill-compatibility-version.mjs's self-test success line hand-transcribed
plus 7 dispatch-gates declaration cases, while the declFailures block it
describes registers only 6 decl(...) calls — a count accurate on the day it was
written, wrong the moment a 7th decl() is added or one is removed. Mirroring the
existing precedent in check-skill-frame-sync.mjs (popCases / pop()), decl()
now increments a declCases counter and the success line prints ${declCases}
instead of the literal.

-  const decl = (label, ok) => { if (!ok) declFailures.push(label); };
+  let declCases = 0;
+  const decl = (label, ok) => { declCases += 1; if (!ok) declFailures.push(label); };
...
-  console.log(`\n✓ check-skill-compatibility-version self-test: ${cases.length} cases pass, plus 7 dispatch-gates declaration cases.`);
+  console.log(`\n✓ check-skill-compatibility-version self-test: ${cases.length} cases pass, plus ${declCases} dispatch-gates declaration cases.`);

Before / after green line

Before (origin/main 572c33a2c4):

✓ check-skill-compatibility-version self-test: 18 cases pass, plus 7 dispatch-gates declaration cases.

After (this PR):

✓ check-skill-compatibility-version self-test: 18 cases pass, plus 6 dispatch-gates declaration cases.

The line moving from 7 to 6 is the expected, correct behaviour change — the
decl(...) block really registers 6 cases today. This is exactly why the issue was
not folded into #15288 (batch 7a), whose proof depended on the self-test's success
line staying byte-identical to main.

Verification — both legs

1. Adding a decl(...) call moves the number. A probe decl('leg-1 probe: an added decl() call must move declCases', true); appended after the existing
   block moved the printed count from 6 to 7:

   ✓ check-skill-compatibility-version self-test: 18 cases pass, plus 7 dispatch-gates declaration cases.
   

2. An unrelated edit does not move the number. Adding an unrelated comment line
   at the top of the file (outside selfTest()) left the printed count at 6:

   ✓ check-skill-compatibility-version self-test: 18 cases pass, plus 6 dispatch-gates declaration cases.
   

   Both probes were reverted before this commit; the working tree diff is exactly
   the two-line fix shown above (git diff confirmed clean before committing).

decl( count in the declFailures block on origin/main 572c33a2c4: 6
(lines 796, 798, 800, 808, 812, 817).

Scope

Only scripts/check-skill-compatibility-version.mjs touched. check-skill-frame-sync.mjs
(the model for this fix) is untouched. This is not assertion-floor work (#13799) —
the derived value is not pinned as a floor, only printed.

Clause-②: no

---

Generated by Claude Code