Add native ReleaseKit bootstrap

docs/release.md

@@ -62,6 +62,18 @@ origin. No repeated release-specific diff review is required.
 
 ## Validate And Publish
 
+For an optional local diagnostic of a committed candidate, run:
+
+```sh
+./scripts/releasekit.sh check vMAJOR.MINOR.PATCH
+```
+
+The candidate must be committed on `main`, use a stable version, and include
+its version-matched release note. See the upstream
+[candidate check contract](https://gitea.maximumdirect.net/eric/ReleaseKit/src/tag/v0.2.0/docs/consumers/check.md)
+for its requirements. This diagnostic is optional and is not required before
+publication.
+
 Run the following with the chosen unused version (replace the placeholder):
 
 ```sh