Public package homepages use the product site

Date: 2026-09-29. Card: t_974d735b, task t_49ea9a88.

The docs-first site already renders the canonical documentation and each twin's README. Package homepages still point into the source repository, which the site can be configured to keep private.

Published twin packages point to https://world.volter.ai/twins/<vendor>. The CLI points to the getting-started guide, the runtime to the CLI reference, and other published World packages to the documentation index. Repository metadata continues to identify the source. The pack scaffold uses the same homepage rule so new twins do not restore the old links.

This changes package metadata for the next release. It does not establish that the site has been deployed or that npm already serves the updated metadata.