docs(changelog): the skills' exact pin

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012jj69kXAVMzAFWH2YeBzN7

Author: claude

CHANGELOG.md

@@ -18,7 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   commit path. The session start only warms that cache in the background and
   names the command; `diffctx-install.sh` and `plugin/checksums.json` are
   gone. The PyPI package gains the `diffctx hook` subcommand the native
-  binary had.
+  binary had. The skills' no-MCP fallback names the same exact version
+  instead of a `<version>` placeholder, and the release bumps it.
 
 ### Fixed