WOOA7S-1696: Premium Analytics: show nested rows and deltas in the Referrers report

[Nikschavan]

Proposed changes

• Remove the performance chart from the Referrers report.
• Match the detailed Calypso Referrers request by summarizing the selected day range, requesting all rows, and omitting the generic days parameter.
• Render referrer groups, sources, and domains as nested rows in the shared drilldown table.
• Show Views comparison deltas when comparison is enabled, while preserving favicons, safe links, error handling, and accessible group context.

Related product discussion/links

• WOOA7S-1696: Report page: Referrers (/reports/referrers)

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

No. It changes how existing Stats referrer data is requested and displayed; it does not add or change tracking.

Testing instructions

• Build Premium Analytics and open Analytics → Referrers.
• Select a date preset and enable comparison.
• Verify the page has no chart and the table shows Referrer and Views columns.
• Verify group, source, and domain rows retain their nested indentation without visible dash markers.
• Verify comparison deltas appear beside Views and referrer favicons and safe external links still work.
• Search for a nested domain and verify its ancestor rows remain visible.
• Automated verification: 79 affected Jest suites (541 tests), TypeScript, ESLint, stylelint, package build, and plugin build pass.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (WordPress.com Site Helper), and enable the update/wooa7s-1696-referrers-report branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack-mu-wpcom-plugin update/wooa7s-1696-referrers-report

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[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 · JS report

[github-actions]

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[Copilot]

Pull request overview

Updates the Premium Analytics Referrers report to align more closely with Calypso’s detailed referrers experience by changing both the Stats request shape and how results are rendered in the report table.

Changes:

• Replace the Referrers report chart + flat records table with a nested (native DataViews hierarchy) drilldown table.
• Change the referrers Stats query/request to summarize explicit date ranges (and omit the generic days param) while requesting all rows for client-side table interactions.
• Surface comparison deltas in the Views column and preserve safe external linking + favicon handling for referrer leaves.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
projects/packages/premium-analytics/routes/reports/referrers/page.tsx	Removes the performance chart and switches the report body to ReportDrilldownTable with native hierarchy configuration.
projects/packages/premium-analytics/routes/reports/referrers/config/use-report-records.ts	Updates the referrers request params (summarized range, all rows) and derives hierarchical rows from merged comparison rows.
projects/packages/premium-analytics/routes/reports/referrers/config/use-report-records.test.ts	Reworks tests to validate the new summarized request and parent-linked hierarchical rows output.
projects/packages/premium-analytics/routes/reports/referrers/config/index.ts	Removes unused aggregate/time-series exports; keeps only the hierarchy flattener export.
projects/packages/premium-analytics/routes/reports/referrers/config/fields.tsx	Updates table fields to support nested rows, safe leaf linking with accessible parent context, favicon handling, and views deltas.
projects/packages/premium-analytics/routes/reports/referrers/config/fields.test.tsx	Adds coverage for parent-context announcements, group-row non-linking, favicon error handling, and views delta rendering.
projects/packages/premium-analytics/routes/reports/referrers/config/fields.module.css	Adds favicon sizing/styling for the referrer label cell.
projects/packages/premium-analytics/routes/reports/referrers/config/aggregate.ts	Replaces bucket-aggregation/time-series helpers with a depth-first hierarchical flattener for DataViews native levels.
projects/packages/premium-analytics/routes/reports/referrers/config/aggregate.test.ts	Updates tests to validate stable parent IDs, depth-first order, and icon inheritance across hierarchy levels.
projects/packages/premium-analytics/packages/ui/src/dataviews-drilldown-native/drilldown-leaf-cell.module.scss	Adjusts link styling override to fix layout without forcing link color/decoration.
projects/packages/premium-analytics/packages/data/src/queries/stats-referrers-query.ts	Configures the referrers query factory to omit days to match Calypso’s explicit-range request style.
projects/packages/premium-analytics/packages/data/src/queries/stats-query.ts	Adds per-endpoint query settings to omit derived params when building Stats proxy queries.
projects/packages/premium-analytics/packages/data/src/queries/tests/stats-queries.test.ts	Adds a regression test ensuring the referrers query key params match the Calypso-style range request (no days).
projects/packages/premium-analytics/changelog/update-wooa7s-1696-referrers-report	Adds a changelog entry describing the report UI change (nested rows + deltas, chart removal).