fix(create-objectstack): exclude CHANGELOG.md from the skills-catalog-boundary ratchet (main red)

The `no customer-facing surface advertises a repo-root skills install` guard
(template-consistency.test.ts) grepped `content/docs`/`skills`/
`packages/create-objectstack` for `skills add objectstack-ai/framework` not
followed by `/skills`, excluding only the test file — not CHANGELOG.md.

When Changesets versioned create-objectstack in RC mode, it baked #3101's
changeset prose into packages/create-objectstack/CHANGELOG.md. That entry
documents the fix by quoting the removed command in past tense
("…advertised `skills add objectstack-ai/framework --all` … now scoped to the
/skills subpath"), which tripped the ratchet and turned Test Core red on main
(pre-existing; first seen at e412fb6 / 631deba, before any of my changes).

A CHANGELOG documenting the REMOVAL of an anti-pattern is not advertising it —
only real customer-facing surfaces (docs, README, index.ts, AGENTS.md, which all
correctly use the /skills subpath) should count. Exclude `**/CHANGELOG.md` from
the guard's grep surfaces. Test-only change; no shipped behavior.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: os-zhuang

packages/create-objectstack/src/template-consistency.test.ts

@@ -318,6 +318,12 @@ describe('skills catalog boundary', () => {
       'packages/create-objectstack',
       // this file mentions the bare form on purpose (needle + error message)
       ':(exclude)packages/create-objectstack/src/template-consistency.test.ts',
+      // CHANGELOGs are auto-generated from changeset prose and legitimately
+      // quote a removed command in past tense while documenting its removal
+      // (#3101: "…advertised `skills add objectstack-ai/framework --all` … now
+      // scoped to the /skills subpath"). Documenting a fix is not advertising
+      // the anti-pattern — only real customer-facing surfaces count.
+      ':(exclude)**/CHANGELOG.md',
     ];
     let candidates = '';
     try {