Premium Analytics: align Stats normalizers with legacy rows

[kangzj]

Fixes #

Proposed changes

• Align Stats traffic row metadata with the legacy Calypso Stats list normalizers.
• Strip parent names from nested referrer labels and preserve the legacy spam-action eligibility logic.
• Preserve link actions for top-author post children and video-play rows.
• Match legacy click child-label behavior by removing only the first parent-name occurrence.
• Add regression tests for the adjusted row metadata.

Related product discussion/links

• Follow-up to Premium Analytics: normalize Stats time-series reports #49779 after comparing the new data layer with the legacy Calypso Stats list normalizers.

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

No. This only adjusts client-side normalization of existing Stats API response data.

Testing instructions

• Run pnpm --dir projects/packages/premium-analytics test --runInBand projects/packages/premium-analytics/packages/data/src/processing/stats.
• Run pnpm --dir projects/packages/premium-analytics typecheck.
• Run pnpm run lint-file projects/packages/premium-analytics/packages/data/src/processing/stats/referrers.ts projects/packages/premium-analytics/packages/data/src/processing/stats/top-authors.ts projects/packages/premium-analytics/packages/data/src/processing/stats/clicks.ts projects/packages/premium-analytics/packages/data/src/processing/stats/video-plays.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/referrers.test.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/top-authors.test.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/clicks.test.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/video-plays.test.ts --max-warnings=0.
• Run pnpm --dir projects/packages/premium-analytics test --runInBand.

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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

[kangzj]

Review-cycle summary - 15e5df0caa -> cfde7a0ffd

2 round(s); CI green; 0 inline threads resolved; Claude feedback addressed.

What changed during the cycle

Commits added:

• cfde7a0ffd - Address review: cover referrer spam URL branch (comment #4785396806)

Diff summary: 1 file changed, 40 insertions(+)

Review feedback addressed:

Source	Comment	Resolution
Claude	#4785396806	Added a regression test for the referrers canSpam URL branch, also pinning single-result label vs spam-domain behavior.

Unaddressed human comments: None.

CI: all required checks passing.

[chihsuan]

Thanks @kangzj LGTM!

One non-blocking thought: Could the new conditionals get a few negative-case tests?

the new conditionals are tested positive-only. A actions: [] assertion for the no-url case (top-authors/video-plays) and a negative canSpam case (url excludes item.name) would catch an over-broad condition later. Not blocking.

[kangzj]

Addressed Chihsuan's review in #49877 (review).

Added negative-case coverage for:

• top authors posts without url -> actions: [] and link: null
• video play rows without url -> actions: [] and link: null
• referrer URL branch where url excludes item.name -> no spam action and actionMenu: 0

Verification:

• pnpm --dir projects/packages/premium-analytics test --runInBand packages/data/src/processing/stats/__tests__/top-authors.test.ts packages/data/src/processing/stats/__tests__/video-plays.test.ts packages/data/src/processing/stats/__tests__/referrers.test.ts
• pnpm run lint-file projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/top-authors.test.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/video-plays.test.ts projects/packages/premium-analytics/packages/data/src/processing/stats/__tests__/referrers.test.ts --max-warnings=0