Always expand filters and legends in reviewed HTML

[Widthdom]

Summary

• serialize reviewed HTML from an export-only clone of the document root
• normalize the clone's Filters and legends panel to expanded without touching the live panel DOM or its localStorage state
• add collapsed and expanded Blob/DOM regression coverage while preserving reviewed state, closed details, visible rows, column widths, and SHA256 generation
• synchronize the generated sample, English/Japanese user and developer documentation, and the Unreleased changelog

Root cause

downloadReviewed() serialized document.documentElement.outerHTML directly after its existing export preparation. As a result, the live filter-zone class, hidden attribute, and aria-expanded value were baked into reviewed HTML unchanged.

Implementation

The existing export preparation and restoration flow remains in place. Immediately before serialization, downloadReviewed() now deep-clones the document root, removes filter-zone-collapsed, removes hidden from #filter-zone-content, and sets #filter-zone-toggle[aria-expanded] to true on that clone only.

Validation

• npm run test:js -- --runInBand — 176 passed
• dotnet test FolderDiffIL4DotNet.Tests/FolderDiffIL4DotNet.Tests.csproj -c Release --no-restore --disable-build-servers -m:1 --filter FullyQualifiedName~HtmlReport --nologo — 240 passed
• Release full suite with Git signing disabled only for test child processes — 2016 passed, 1 skipped, 0 failed
• git diff --check — passed

The local cdidx refresh indexed all changed source/docs/sample files. Its only partial entries were the known CodeIndex JSON extraction issue for version.json and package-lock.json (Widthdom/CodeIndex#4710).