Tree

What the tree lists ("Folders", "Categories"). Not visible unless `showLabel`.

Accessibility: aria-label / accessibilityLabel on the tree.

Show the label as a Heading above the tree (then the tree is aria-labelledby it instead of aria-label).

Heading level of the visible label in the page outline; its size is headingSize regardless. On React Native the level has no observable effect — Heading sets the header trait at every level and headingSize pins the size — so the prop is accepted and forwarded for parity only, as DataGrid's captionLevel.

The hierarchy. `href` makes a node's label a Link with `tone: inherit` nested inside the label Text, so it takes the label's font and color (navigation trees); `icon` is an Icon glyph (`folder` and `file` exist for the usual case); `badge` is a short trailing count or status; `children: "lazy"` loads on first expand through `onExpand`.

Controlled expanded ids. A still-`"lazy"` id here is held closed until the user opens it, exactly as in `defaultExpanded` — the id stays in the array the caller passed and in what onExpandChange reports, but the node does not render open and fires no onExpand.

Initially expanded ids. `["*"]` opens every node whose `children` is a non-empty array and never a `"lazy"` node, as TreeGrid; `"*"` is reserved as that sentinel, so it is never matched against an id — a node whose id is literally `"*"` is opened only as any other loaded parent is, and is never treated as explicitly listed (so a lazy one stays closed). The first user toggle resolves `"*"` to the concrete ids then open, and that resolved array is what onExpandChange reports, any held-lazy ids kept in place, as TreeGrid. A lazy id listed explicitly stays closed until the user opens it (onExpand only fires for user acts), and the same rule covers the controlled `expanded`.

`single`: one current node (the usual for navigation and pickers). `multiple`: checkbox-like selection with Space, Shift+arrows and Ctrl+A; parents are checkboxes that cascade when `selectChildren`. `none`: expand/collapse only.

Controlled selected ids. Always an array, even in `single` mode (zero or one element).

Initially selected ids.

With `multiple`, selecting a parent selects its descendants and parents show indeterminate. The cascade covers loaded, enabled descendants only (a `"lazy"` subtree contributes nothing until loaded); a parent's id is in `selected` exactly when all its enabled loaded descendants are, and unchecking any descendant removes it and every ancestor id. Its aria-checked (true, mixed, false) is derived from its descendants. A disabled node is skipped as a target but does not wall off its subtree: its enabled loaded descendants still cascade. A parent with no enabled loaded descendants at all (a still-lazy subtree, or only disabled children) behaves as a leaf and carries just its own id. Shift+ArrowDown/Up cascade like Space but only ever add — they never remove a node or an ancestor.

With `single`, moving focus also selects (a settings sidebar where the tree drives a panel). Moving focus means the keyboard — the arrows, Home, End and type-ahead; entering the tree with Tab and focus arriving from a pointer never select on their own (a click already selects, and mere entry should not report a selection change). Off by default: focus moves, Enter or Space selects.

Vertical guide lines under open parents.

Fired with the selected ids, in tree (document) order, and only when the set actually changes (Space on the already-selected node, or selectOnFocus landing on it, fires nothing).

Fired with the expanded ids, in the order they were opened.

Fired with its id each time a node whose `children` is still `"lazy"` is opened, so a failed load can retry (as TreeGrid): closing and reopening the node fires it again, and replacing `children` is the only thing that stops it — it is not once per mount. It fires before the onExpandChange of the same act.

Fired on Enter or double-click on a node (open the file, navigate), with its id. Nodes with `href` navigate instead.