fix(ci): skip changeset-check on the version-packages PR

The changesets bot's "chore: version packages" PR (branch
changeset-release/main) consumes changesets — it deletes the .md files
and bumps versions, adding none. The changeset-check job counts only
added/modified .changeset/*.md files (--diff-filter=AM), so it always
reported 0 and failed on that PR (e.g. #22), even though the PR is
correct by construction.

Guard the job so it runs for normal PRs but skips the bot's version PR:
`github.head_ref != 'changeset-release/main'`.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: alerizzo

.changeset/skip-changeset-check-on-version-pr.md

@@ -0,0 +1,7 @@
+---
+---
+
+Internal CI change (no version bump): skip the `changeset-check` job on the
+changesets bot's "version packages" PR (`changeset-release/main`). That PR
+consumes (deletes) changesets rather than adding them, so the check counted 0
+added/modified changeset files and always failed.

.github/workflows/ci.yml

@@ -39,7 +39,9 @@ jobs:
         run: npm test
 
   changeset-check:
-    if: github.event_name == 'pull_request'
+    # Skip the changesets bot's "version packages" PR: it consumes (deletes)
+    # changesets rather than adding them, so it would always fail this check.
+    if: github.event_name == 'pull_request' && github.head_ref != 'changeset-release/main'
     runs-on: ubuntu-latest
 
     steps: