docs(apps): add migration guide, update links; remove bin/{oli,ofs} (#6689) (#6705)

* docs(apps): add migration guide and update oli/ofs pages with new repos (#6689)

Add website/docs/40-apps/migration.mdx; update oli/ofs docs to link to new repositories;

* ci(scripts): make PACKAGES robust when bin/ is absent (#6689)

constants.list_packages() now skips non-existent directories (bin removed after splitting apps).

Author: tao12345666333