feat(library-publish): prod marks one release "Latest", chosen by latest-release

[beplus-agent-claude]

After the catch-up promotions, every version prod has is a full release on GitHub, but the "Latest" badge didn't move. beplus/cdk still showed cdk_v0.8.0 (March) with 0.9.0 in prod, and beplus/docs showed docs_v0.4.2 (February) with 1.0.0-next.17 in prod.

prod turned pre-releases into full releases without --latest, and GitHub doesn't move the badge on that edit. This was true before #15 as well; the catch-up just made it visible. A repository of several packages has one badge for all of them, so the workflow has to be told which.

The change

• New optional input latest-release: the package whose release prod marks "Latest".
• Defaults without it: the repository's only package, or else the package named after the repository (@beplus/cdk in beplus/cdk). With neither, prod leaves the badge alone.
• New prod step "Mark the Latest GitHub release": sets --latest on that package's release at the promoted commit. It runs on every prod promotion, so the badge always matches prod's latest, and a stale badge like cdk_v0.8.0 gets fixed on the next promotion.
• Making a release full now always passes --latest=false, so only that step moves the badge.
• README updated.

Across the 17 libraries

• Only package (11): api, auth, aws, cms, config, mobile, rush, saas, server, uix, web.
• Named after the repository (3): cdk, database, docs.
• No badge for now (3): ai, analytics and data each publish several packages, none named after the repository. The plan is for every repository to gain a package named after it, which this default then picks with no input to set.

Tested

Not run on GitHub yet. Locally, both prod release steps ran against a stubbed gh (shellcheck clean):

• one package
• several packages, one named after the repository, even when listed after cdk-release
• several packages, none named after the repository
• an explicit latest-release
• a latest-release naming a package the repository doesn't publish: warning
• a chosen package with no GitHub release: warning
• the @beplus/cdk / @beplus/cdk-release prefix trap

After merge

• Tag v2.12.0 and move v2.
• The next prod promotion in each repository sets its badge. Dispatch Publish on prod to set it now.