feat(core): useTypeahead hook + DropdownMenu integration (menus-11)

[cixzhang]

Part of the accessibility & keyboard-management program (#3343). Adds the typeahead primitive the audit calls for (infra-14) and closes menus-11 for DropdownMenu.

What this adds

useTypeahead — a first-character ("type-to-focus") search hook:

• Buffers printable keystrokes and resets after 750ms of inactivity.
• Matches items whose label starts with the buffer; cycles from the current index, so pressing the same letter repeatedly walks through matches (astryx's Selector typeahead restarted at 0 and stuck on the first match).
• Skips disabled indices; reserves a bare Space for activation (only extends the query mid-buffer).
• Additive and collection-agnostic — it doesn't move focus itself; the caller wires onMatch to its own focus/selection (e.g. useListFocus.focusItem). No change to useListFocus/useGridFocus, so it's independent of the roving-engine consolidation discussion.

Wired into DropdownMenu

DropdownMenu's key handler now runs typeahead before arrow navigation — typing a letter jumps to the matching menu item. Menus previously had no typeahead (an APG Menu requirement).

Tests

useTypeahead.test.tsx (7): match, buffer accumulation, same-letter cycling + wrap, timeout reset, disabled-skip, control/modifier ignore, bare-Space ignore. DropdownMenu.test.tsx (+1): typing focuses the matching item. Full suites green (39 tests), typecheck + lint clean.

Follow-up

Wire useTypeahead into ContextMenu/NavMenu/MoreMenu (same listKeyDown seam) and the Selector family (replace its restart-at-0 matcher) — deferred to focused follow-ups.

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Project	Deployment	Actions	Updated (UTC)
astryx	Ready	Preview, Comment	Jul 2, 2026 6:49pm

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No new or modified components detected.

Bundle Size Summary

Package	Size (ESM)	Size (CJS)	Gzipped
@astryxdesign/core	N/A	4.6KB	0B

Accessibility Audit

Status: No accessibility violations detected.

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[cixzhang]

fix conflicts