feat(voice): per-account choice between Whisper and the browser; STT_ALLOW_BROWSER

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/domain/models.go

@@ -143,6 +143,8 @@ type User struct {
 	NotificationSettings *NotificationSettings `json:"notificationSettings,omitempty"`
 	// DoneRetentionDays: completed tasks are deleted this many days after ticking them off (0 = never)
 	DoneRetentionDays int `json:"doneRetentionDays"`
+	// VoiceInput: "" uses the server's Whisper (when set up), "browser" the browser's recognition
+	VoiceInput string `json:"voiceInput"`
 }
 
 // NotificationSettings: which events reach a user over which channel, the daily summary and a pause.