feat: add semantic click events on child components (ListItem, MenuItem, Tab, etc.)

Problem

Several container components fire click/press events on behalf of their children (e.g., List fires item-click, Menu fires item-click), but the child elements themselves have no public click event. This means framework consumers (React, Angular, Vue) using wrappers like createReactComponent cannot attach onClick handlers directly on child elements — they must listen on the parent and match the clicked item from the event detail.

For example, React consumers expect to write:

<ListItemStandard onClick={() => handleClick()}>Product A</ListItemStandard>

But currently must write:

<List onItemClick={(e) => { if (e.detail.item === targetRef) handleClick(); }}>
  <ListItemStandard>Product A</ListItemStandard>
</List>

Prior Art

This pattern has already been implemented for:

• TableRow — fires own click + Table keeps row-click (#13303)
• TableRowActionBase — fires own click + Table keeps row-action-click
• SideNavigationSelectableItemBase — fires own click + SideNavigation keeps item-click
• Button, Link, Icon, CardHeader, Tag, Avatar — all suppress the native click and fire a semantic CustomEvent("click") covering mouse + keyboard

The pattern: intercept the native DOM click on the child via stopImmediatePropagation, fire a CustomEvent("click") via fireDecoratorEvent, then call the parent's handler for backward compatibility.

Candidates

High impact

Child Component	Parent Component	Parent Event	Mechanism
ListItemBase (all variants)	List	item-click	Private _press event → List re-fires
MenuItem	Menu	item-click	Via inner List's item-click
TreeItemBase / TreeItem	Tree	item-click	Via inner List's item-click
NotificationListItem	NotificationList	item-click	Private _press → inner List → parent
UserMenuItem	UserMenu	item-click	Via inner List's item-click

Note: ListItemBase is the foundation. Adding a semantic click there would cascade to MenuItem, TreeItem, NotificationListItem, and all other ListItem variants.

Medium impact

Child Component	Parent Component	Parent Event	Mechanism
Tab	TabContainer	tab-select	Pure DOM delegation, no child event
BreadcrumbsItem	Breadcrumbs	item-click	Internal Link click, parent maps to item
SegmentedButtonItem	SegmentedButton	selection-change	Pure DOM delegation, no child event
WizardTab	Wizard	step-change	Private selection-change-requested

Low impact

Child Component	Parent Component	Parent Event
ColorPaletteItem	ColorPalette	item-click

Implementation approach

For each candidate:

1. Declare click in the base class eventDetails (to preserve JSX type compatibility in the hierarchy)
2. Add @eventStrict("click", { bubbles: true }) on the concrete child class
3. Intercept the native click in the constructor (this.addEventListener("click", ...)) — suppress via stopImmediatePropagation, fire fireDecoratorEvent("click")
4. Keep the existing parent-level event (item-click, tab-select, etc.) for backward compatibility

Suggested order

1. ListItemBase — highest impact, cascades to Menu, Tree, NotificationList
2. Tab — commonly requested by framework consumers
3. BreadcrumbsItem / SegmentedButtonItem — smaller scope, straightforward

Start with ListItemBase and compare the existing TableRow, TableRowActionBase, and SideNavigationSelectableItemBase patterns. Trace how List, Menu, and Tree currently propagate their parent events, then determine the candidate scope before changing child event declarations and handlers. Done means selected child components expose semantic click events while existing parent-level events remain compatible.