JavaScript migration tool transition

The JavaScript migration engine and npm package now live in honua-io/honua-migrate. Install @honua/honua-migrate and use the JavaScript-specific executable:

npm install --save-dev @honua/honua-migrate
npx honua-js-migrate scan ./src
npx honua-js-migrate codemod ./src --write --report migration-report.json

Existing imports from @honua/sdk-js/migration remain valid and forward to @honua/honua-migrate. The SDK's scan:arcgis, scan:arcgis:widgets, and migrate:arcgis npm scripts also delegate to the new executable. Both compatibility paths write a deprecation notice to stderr without changing stdout, exit status, or migration artifacts.

The forwarders will remain for at least two consecutive honua-migrate minor releases and 90 days. They will not be removed before honua-migrate 1.2.

The canonical Python executable remains honua-migrate; the JavaScript executable is honua-js-migrate, avoiding a global command-name collision.