TreeView is not RTL-safe (chevron, indent, and guide lines are hard-coded LTR)

[czarandy]

Problem

The library's convention is RTL-safe styling (_rtl mirroring, LogicalChevron*, logical properties — used by Pagination, Calendar, Lightbox, Drawer, SideNav, etc.), but TreeView is entirely physical:

• The disclosure chevron is a raw ChevronRight with no _rtl mirror (src/components/TreeView/TreeViewItem.tsx:271), rotated 90° when expanded (TreeViewItem.recipe.ts:176). In RTL the collapsed arrow points away from the content. (Contrast: Table row expansion already uses LogicalChevronEnd.)
• Item indentation uses physical marginLeft (TreeViewItem.tsx:350).
• Branch guide lines are positioned with physical left (src/components/TreeView/TreeViewBranches.tsx:39,47).

Keyboard handling already does the right thing (TreeView.tsx:280-285 swaps ArrowLeft/ArrowRight in RTL), which makes the visual mismatch worse.

Expected

Under dir="rtl", the tree mirrors: chevron points toward the content when collapsed, indentation grows from the inline-start edge, guide lines sit on the inline-start side.

Suggested fix

Use LogicalChevronEnd (or add the _rtl: scaleX(-1) mirror) for the disclosure icon, and migrate marginLeft/left to marginInlineStart/insetInlineStart. Verify with an RTL Storybook example.