[codex] Fix treemap parent select fill with upperLabel

[susiwen8]

Summary

• keep parent treemap nodes with upperLabel using their configured select.itemStyle.color
• add a regression test covering parent-node select styling with upper labels

Root Cause

The parent-node upperLabel rendering path hardwired the selected fill color to borderColor, so parent nodes ignored select.itemStyle.color. That broke parent-node selected styling and led to the hover/select behavior reported in the issue.

Validation

• ./node_modules/.bin/jest --config test/ut/jest.config.cjs --runInBand test/ut/spec/series/treemap.test.ts
• ./node_modules/.bin/eslint src/chart/treemap/TreemapView.ts test/ut/spec/series/treemap.test.ts

Fixes #21433

[echarts-bot]

Thanks for your contribution!
The community will review it ASAP. In the meanwhile, please checkout the coding standard and Wiki about How to make a pull request.

The pull request is marked to be PR: author is committer because you are a committer of this project.

To reviewers: If this PR is going to be described in the changelog in the future release, please make sure this PR has one of the following labels: PR: doc ready, PR: awaiting doc, PR: doc unchanged

This message is shown because the PR description doesn't contain the document related template.

[Copilot]

Pull request overview

Fixes treemap parent-node selection styling when upperLabel is enabled by ensuring the selected background fill honors select.itemStyle.color (instead of being hardwired to borderColor), and adds a regression unit test for this behavior.

Changes:

• Update treemap parent-node background select-state fill logic to prefer select.itemStyle.color, with fallbacks.
• Add a unit test asserting parent nodes with upperLabel use select.itemStyle.color for the select state fill.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/chart/treemap/TreemapView.ts	Adjusts select-state fill computation for parent-node background rendering when upperLabel is used.
test/ut/spec/series/treemap.test.ts	Adds a regression test validating the parent-node select fill uses select.itemStyle.color with upperLabel.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

The changes brought by this PR can be previewed at: https://echarts.apache.org/examples/editor?version=PR-21575@1e2a3cf

[Ovilia]

Can we have an HTML test for this case?

[susiwen8]

Added a browser-level regression case in \ on top of the existing Jest regression. The new HTML page exercises the \ parent-node case directly in the browser.

[susiwen8]

Added a browser-level regression case in test/treemap-upperLabel-select.html on top of the existing Jest regression.

The new HTML page exercises the upperLabel + select.itemStyle.color parent-node case directly in the browser.