Premium Analytics: add Stats app publish state endpoint

[kangzj]

Fixes #

Proposed changes

• Add Premium Analytics data package support for the Stats app site published state signal.
• Fetch the published-state boolean from the existing WordPress.com site-has-never-published-post endpoint through the Premium Analytics proxy.
• Wire the query, hook, public exports, proxy-backed query test, and changelog entry.

Related product discussion/links

• Builds on Premium Analytics: add Stats endpoint foundation #49886.

Does this pull request change what data or activity we track or use?

No. This only adds typed client data/query integration for an existing site-state signal.

Testing instructions

• CI=true pnpm --dir projects/packages/premium-analytics test -- packages/data/src/queries/__tests__/stats-queries.test.ts packages/data/src/hooks/__tests__/stats-exports.test.ts --runInBand
• CI=true jp test php packages/premium-analytics -v
• CI=true pnpm --dir projects/packages/premium-analytics run typecheck
• CI=true pnpm exec eslint --max-warnings=0 projects/packages/premium-analytics/packages/data/src/queries/stats-app-site-has-never-published-post-query.ts projects/packages/premium-analytics/packages/data/src/queries/__tests__/stats-queries.test.ts projects/packages/premium-analytics/packages/data/src/hooks/use-stats-app-site-has-never-published-post.ts projects/packages/premium-analytics/packages/data/src/hooks/index.ts projects/packages/premium-analytics/packages/data/src/index.ts projects/packages/premium-analytics/packages/data/src/queries/index.ts
• git diff --check

[jp-launch-control]

Code Coverage Summary

No summary data is available for parent commit 7db3be9, so cannot calculate coverage changes. 😴

If that commit is a feature branch rather than a trunk commit, this is expected. Otherwise, this should be updated once coverage for 7db3be9 is available.

Full summary · PHP report

[github-actions]

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[kangzj]

Review-cycle audit: clean. Latest Claude app re-review is non-blocking, there are no inline review threads, and GitHub reports no required checks for this branch. No code changes were needed; only non-required coverage/label checks remain pending.