feat(desktop): add keyboard navigation to clarify choices

[mapu-og]

Summary

• add a visual keyboard cursor to the Desktop clarify choices
• support circular ArrowUp / ArrowDown navigation across every choice and the trailing Other field
• support direct numeric selection with 1–9, while preserving the existing A/B/C shortcuts
• let Enter confirm the selected answer or the currently highlighted row
• keep global shortcuts inactive while the user is typing in an input, textarea, or editable field

Motivation

The Desktop clarify card already supports mouse input and letter shortcuts, but keyboard-heavy workflows still require users to target a specific letter or reach for the mouse. This makes the card behave like the other keyboard-oriented pickers in the app without changing the clarify.respond protocol or any backend behavior.

Behavior

• arrow navigation wraps between the first choice and Other
• moving the cursor clears any stale selection so the highlighted row is the source of truth
• numeric and letter shortcuts select the corresponding answer
• the number/letter after the final choice focuses Other
• Enter submits an existing answer; with no explicit selection it submits the highlighted choice or focuses Other
• shortcuts stand down while an input, textarea, or content-editable element has focus

Test plan

• npx vitest run src/components/assistant-ui/clarify-tool.test.tsx — 9 tests passed
• npm run typecheck
• npx eslint src/components/assistant-ui/clarify-tool.tsx src/components/assistant-ui/clarify-tool.test.tsx — 0 errors
• npx prettier --check src/components/assistant-ui/clarify-tool.tsx src/components/assistant-ui/clarify-tool.test.tsx
• npm run build

Scope

Desktop renderer only. No tool schema, gateway, session, profile, or backend changes.

[teknium1]

Thanks for the focused Desktop keyboard-navigation work. The feature is still absent on current main: apps/desktop/src/components/assistant-ui/clarify-tool.tsx:308-353 supports letter shortcuts only, with Enter limited to an existing answer.

Problems

• The new unqualified Enter path at apps/desktop/src/components/assistant-ui/clarify-tool.tsx:400-406 is registered once per mounted clarify card. Current main mounts chat surfaces for the primary and every tile (apps/desktop/src/app/chat/index.tsx:428-431) and scopes each card to its own session request (clarify-tool.tsx:188-192). One body-level Enter could therefore answer multiple pending clarifications.
• The new tests mount one card only (clarify-tool.test.tsx:67-80), so this multi-session path is untested.

Suggested changes

• Gate shortcut handling to the focused clarify/session surface and add a primary-plus-tile regression test asserting only that request receives clarify.respond.
• Salvage onto current main's session-scoped clarify implementation; GitHub currently reports this PR as dirty against main.

Automated hermes-sweeper review.

[teknium1]

On current main, clarify cards can be mounted simultaneously for the primary surface and session tiles (apps/desktop/src/app/chat/index.tsx:428-431), each with a session-scoped request. Every ready card receives this window-level Enter and can call activateActive(), so a single Enter can answer multiple requests. Gate this to the focused clarify/session surface and add a multi-card regression test.

[OutThisLife]

Superseded by #69799 — cherry-picked (authorship preserved) and re-authored onto the merged ChoiceButton + sanitized choice pipeline. Arrow/number/letter nav, Enter-to-confirm, and the full a11y wiring are all carried over with your tests. Thanks @mapu-og! Closing in favor of the rebased version.