DataView: expose classNames for filter-chip internals and loader rows

DataView.List と FilterChip の実装から始め、Filters.classNames.filterChips と DataViewListClassNames がレンダリングされた要素にどのように適用されているかを追跡します。リストされた filter-chip の内部要素と、ローディングコンテナまたは行にフックを追加し、既存の classNames パターンを維持します。ハッシュ化された CSS-module セレクターなしで両方の領域をテーマ設定できれば完了です。

Summary

DataView.List renders its rows, cells, and group headers internally, and exposes classNames hooks for them (root, header, headerCell, row, cell, groupHeader, plus per-column cell/header and Filters.classNames.filterChips/addFilter). Two rendered parts still have no hook, so theming them means targeting hashed CSS-module classes ([class*="data-view-module_…"]), which are internal and can change between releases.

What has no hook

1. Filter-chip internals. Filters.classNames.filterChips lands on the chip root only. The inner parts can't be reached: chip-label, operationText, operationValue, selectValue, removeIcon, removeIconContainer, leadingIcon.

2. Loader / skeleton rows. When isLoading renders placeholder rows, there's no hook on the loader container or its rows — DataViewListClassNames covers real rows, not the loading state.

Proposed change

1. Add a classNames object to FilterChip (surfaced through Filters) covering its inner parts.
2. Add a loader (and/or loader-row) key to DataViewListClassNames.

Both follow the pattern the existing hooks already use: read an optional string from props, apply it to the element DataView already renders.

Willing to contribute

Happy to open a PR if the approach looks right.