Add workflow_dispatch to release workflow and document changeset test anti-pattern

- Add workflow_dispatch trigger to release-npm.yml so releases can be
  manually re-triggered when the automatic path-based trigger misses.
- Document in CLAUDE.md and AGENTS.md that tests must never assert
  .changeset file existence, since changeset version consumes them.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/release-npm.yml

@@ -1,6 +1,7 @@
 name: Release npm packages
 
 on:
+  workflow_dispatch:
   push:
     branches:
       - main

AGENTS.md

@@ -17,6 +17,10 @@ These rules are repo-specific and apply to everything under this directory.
 - For release or packaging changes, run `npm run ci`.
 - Keep release docs, workflow files, and package metadata aligned in the same change.
 
+## Testing anti-patterns
+
+- **Never write tests that assert `.changeset/*.md` files exist.** Changesets are consumed (deleted) by `changeset version` during the release flow. Any test guarding changeset file presence will break CI on the version-bump commit and block the release pipeline.
+
 ## Development skill install rules
 
 - When testing or developing skills from this repository, install or sync the current skill directories into the user's home-directory global skill locations first.

CLAUDE.md

@@ -0,0 +1,5 @@
+# k-skill
+
+## Testing anti-patterns
+
+- **Never write tests that assert `.changeset/*.md` files exist.** Changesets are consumed (deleted) by `changeset version` during the release flow. Any test guarding changeset file presence will break CI on the version-bump commit and block the release pipeline.