# Issue #260 Artifact — Phone/client no-audio guard (primary-device only playback)

## Scope
Added regression coverage for MVP audio policy to ensure phone/client flows never claim playback ownership, while primary-device playback stays unaffected.

## Acceptance mapping
1. **client/phone triggers no playback**
   - Existing test coverage retained in `player-shell.component.spec.ts`:
     - `does not trigger original media play during player-shell init path`
     - `installs secondary-device audio guard while player shell is mounted`
2. **primary device playback unaffected**
   - New negative test in `player-shell.component.spec.ts`:
     - `keeps primary-device playback untouched when no-audio capability is disabled`
3. **one negative test for phone audio**
   - Existing negative path preserved:
     - `does not trigger original media play during player-shell init path`
4. **no backend contract changes**
   - Frontend test/docs-only scope; no backend contract files changed.