Background

The app ships 45 .aac sound effects inherited from OpenCode (packages/ui/src/assets/audio/). They don't fit PawWork's tone, and the surrounding behavior is tangled:

• Three separate sound toggles (agent / permissions / errors) plus three separate system-notification toggles.
• Sounds are played in two places — context/notification.tsx (turn-complete + error) and pages/layout/layout-sdk-event-effects.ts (permission) — and are never gated by whether the session is currently on screen.
• Every event can fire twice: the app plays its own sound and the OS notification fires with its own sound.

Goal (confirmed design)

1. When it sounds — "your turn" events (turn complete / question / permission) play one warm sound; a real error plays a second sound. Manual interrupts, reverts, and in-progress hiccups never sound.
2. What it sounds — exactly two bundled sounds (notify.aac, error.aac), warm and soft. No per-sound picker.
3. Relation to OS notifications — the app owns the sound; the OS notification is silenced (banner + click-to-focus only), so no double sound.
4. Settings — one three-state control governing all of the above uniformly: Never / Only when unfocused (default) / Always. Error follows the same control: only "Never" silences it, otherwise it ignores the focus state.

Audio is decided: a soft cooking-bell ding for "your turn", a low restrained tap for "error" (sources + licenses recorded in the Phase 1 PR).

Delivery (phased)

• Phase 1 — ship the sounds (first PR): delete the 45 OpenCode .aac, add notify.aac + error.aac, point existing defaults at them, collapse the picker options, drop the 45 i18n option labels. Low risk; ships the new sounds without touching behavior.
• Phase 2 — behavior refactor (follow-up PR): single three-state setting, silence OS notifications, unify "only when unfocused" gating across sounds + banners, settings migration, settings UI rewrite, i18n cleanup, DESIGN.md sound spec. Detailed file-by-file plan in the first comment.