Document the manual npm publish reminder in the release process

The obsidian-local-rest-api npm package -- the types module extension
authors install -- can only be published manually because of how the
maintainer's npm authentication is set up; it cannot run in CI and
cannot be performed by an assistant. Releases had no step covering it,
which is how the published package drifted to a two-year-stale 2.5.4
while the plugin moved on to 5.x. The release process now ends with
checking whether the extension API changed since the previous tag and,
when it has, reminding the user to run npm publish themselves.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>