The completion chime on `/agents` was enabled by default for new users
(or when no localStorage preference existed). This changes the default
to disabled, so users must explicitly opt in via the sound toggle
button.
## Changes
- `getChimeEnabled()` now returns `false` when no preference is stored
(was `true`)
- `catch` fallback also returns `false` (was `true`)
- Updated tests to reflect the new default and explicitly enable the
chime in `maybePlayChime` tests
Kyle Carberry
af1be592cf