GET /api/settings returned the whole settings.json to every signed-in user.
An admin's App Settings save stores the Deepgram key there
(voiceSettings.apiKey), so any regular user could read it, and their
browser copied it into its own voice config and dictated on the admin's
account. caseOrder and lastUsedCase also named the admin's cases.
In multi-user mode a non-admin now reads the file without those three
(settingsForNonAdmin). Admins and single-user mode get the file as it
is. Pinned by route tests and the live multi-user test.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>