Premium Analytics: add Stats app referrers spam endpoint

[kangzj]

Fixes #

Proposed changes

• Add Premium Analytics data package support for the Stats app referrers spam endpoint, following the Stats endpoint patterns established in Premium Analytics: add Stats endpoint foundation #49886.
• Wire the endpoint-specific query, hook, public exports, and sanitizer/normalizer registration where applicable.
• Keep endpoint typing tied to sanitizer keys or passthrough query inference, with focused fixtures/tests for the raw endpoint payload shape where normalization is introduced.

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 Stats API endpoint.

Testing instructions

• 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
• pnpm exec eslint --max-warnings=0
• pnpm --dir projects/packages/premium-analytics run typecheck
• git diff --check

[jp-launch-control]

Code Coverage Summary

This PR did not change code coverage!

That could be good or bad, depending on the situation. Everything covered before, and still is? Great! Nothing was covered before? Not so great. 🤷

Full summary · PHP report

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ Add a "[Status]" label (In Progress, Needs Review, ...).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
2. Make sure to test your changes on all platforms that it applies to. You're responsible for the quality of the code you ship.
3. You can use GitHub's Reviewers functionality to request a review.
4. When it's reviewed and merged, you will be pinged in Slack to deploy the changes to WordPress.com simple once the build is done.

If you have questions about anything, reach out in #jetpack-developers for guidance!

[kangzj]

Review-cycle audit complete: latest Claude re-review has no blocking issues, no inline review threads are open, the branch is mergeable against endpoint/stats-endpoint-foundation, and there are no failing checks. Remaining Claude notes are optional/non-blocking, and the PR is ready for team review.