fix(dropdown): keep focus on trigger with single-component keyboard navigation

[driskull]

Related Issue: #8206

Summary

This PR updates calcite-dropdown keyboard/focus behavior to keep focus on the trigger and represent item navigation via an active-descendant style state, aligning with the “single component” focus model requested in #8206.

Changes:

• Refactors dropdown keyboard handling to track an internal active item index and activate items without moving DOM focus into dropdown items.
• Adds an activeDescendant state to calcite-dropdown-item (with styling) and wires up ariaActiveDescendantElement for the menu.
• Updates E2E and browser tests to assert active-descendant behavior instead of document.activeElement moving to items.

[Copilot]

Pull request overview

This PR updates calcite-dropdown keyboard/focus behavior to keep focus on the trigger and represent item navigation via an active-descendant style state, aligning with the “single component” focus model requested in #8206.

Changes:

• Refactors dropdown keyboard handling to track an internal active item index and activate items without moving DOM focus into dropdown items.
• Adds an activeDescendant state to calcite-dropdown-item (with styling) and wires up ariaActiveDescendantElement for the menu.
• Updates E2E and browser tests to assert active-descendant behavior instead of document.activeElement moving to items.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/components/src/components/dropdown/resources.ts	Removes internal ID helpers previously used for menu/button relationships.
packages/components/src/components/dropdown/interfaces.ts	Removes the internal keyboard event detail type no longer used.
packages/components/src/components/dropdown/dropdown.tsx	Implements active-descendant navigation and keeps focus on the trigger; adds hover focus-in/out handlers.
packages/components/src/components/dropdown/dropdown.e2e.ts	Updates focus assertions to check active-descendant rather than focused item.
packages/components/src/components/dropdown/dropdown.browser.e2e.tsx	Updates browser-level tests, including hover behavior expectations.
packages/components/src/components/dropdown-item/dropdown-item.tsx	Adds activeDescendant and activateItem(), removes item-level keydown handling, sets item tabIndex to -1.
packages/components/src/components/dropdown-item/dropdown-item.scss	Applies focus styling when active-descendant is set.
packages/components/src/components/dropdown-item/dropdown-item.e2e.ts	Removes key-activation coverage that depended on item receiving focus.
packages/components/src/components/dropdown-item/dropdown-item.browser.e2e.tsx	Replaces generic disabled tests with event-prevention assertions.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Comments suppressed due to low confidence (1)

packages/components/src/components/dropdown-item/dropdown-item.tsx:169

• calcite-dropdown-item no longer listens for keyboard activation when it has focus (the keydown handler was removed). Since the host can still receive focus programmatically (and sometimes via pointer interaction even with tabIndex=-1), Enter/Space will no longer activate/select the item, which is a regression from prior behavior and can hurt accessibility in edge cases. Consider keeping minimal key handling for Enter/Space (and possibly Escape) when the item itself is focused, even if arrow-key navigation remains managed by calcite-dropdown.

  constructor() {
    super();
    this.listen("click", this.onClick);
    this.listenOn<CustomEvent>(
      document.body,
      "calciteInternalDropdownItemChange",
      this.updateActiveItemOnChange,
    );
  }

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