fix(task-activity): revamp ask-user-question ui

[astyfx]

Summary

Fix the Task Activity layout while Ask User Question is pending and refresh the question interaction UX around a focused response composer.

Changes

Fixes

• task-activity: collapse duplicate activity rows while the pending interaction composer owns attention, preserving the waiting state and natural composer spacing.
• ask-user-question: redesign the response card with accessible radio/checkbox controls, custom answers, explicit Continue and Decline actions, and compact settled-state summaries.
• interaction layout: cover keyboard navigation, 44px touch targets, 375px responsive layout, light/dark themes, and additional-context divider spacing.

Test Evidence

• bun run test:ci — passed all 305 isolated test files, reliability/max-lines/switch gates, typecheck, renderer build, and desktop build.
• bun run test:e2e -- tests/e2e/turn-activity.e2e.ts --project=chromium — 2 passed.
• bun test tests/user-input-card.test.tsx tests/turn-activity-render.test.tsx — 9 passed.

Notes

• No provider, preload, IPC, or persistence contracts changed.
• No breaking changes.

[heath-s]

Approved