feat(BRIDGE-37): Remote notification support

internal/frontend/grpc/bridge.proto

@@ -277,6 +277,7 @@ message AppEvent {
     KnowledgeBaseSuggestionsEvent knowledgeBaseSuggestions = 12;
     RepairStartedEvent repairStarted = 13;
     AllUsersLoadedEvent allUsersLoaded = 14;
+    UserNotificationEvent userNotification = 15;
   }
 }
 
@@ -545,6 +546,14 @@ message SyncProgressEvent {
   int64 remainingMs = 4;
 }
 
+message UserNotificationEvent {
+  string title = 1;
+  string subtitle = 2;
+  string body = 3;
+  string userID = 4;
+}
+
+
 //**********************************************************
 // Generic errors
 //**********************************************************

internal/frontend/grpc/event_factory.go

@@ -18,6 +18,7 @@
 package grpc
 
 import (
+	"github.com/ProtonMail/proton-bridge/v3/internal/events"
 	"github.com/ProtonMail/proton-bridge/v3/internal/kb"
 	"github.com/bradenaw/juniper/xslices"
 )
@@ -249,6 +250,16 @@ func NewAllUsersLoadedEvent() *StreamEvent {
 	return appEvent(&AppEvent{Event: &AppEvent_AllUsersLoaded{AllUsersLoaded: &AllUsersLoadedEvent{}}})
 }
 
+func NewUserNotificationEvent(event events.UserNotification) *StreamEvent {
+	return appEvent(&AppEvent{Event: &AppEvent_UserNotification{
+		UserNotification: &UserNotificationEvent{
+			UserID:   event.UserID,
+			Title:    event.Title,
+			Subtitle: event.Subtitle,
+			Body:     event.Body,
+		}}})
+}
+
 // Event category factory functions.
 
 func appEvent(appEvent *AppEvent) *StreamEvent {

internal/frontend/grpc/service.go

@@ -404,6 +404,9 @@ func (s *Service) watchEvents() {
 
 		case events.AllUsersLoaded:
 			_ = s.SendEvent(NewAllUsersLoadedEvent())
+
+		case events.UserNotification:
+			_ = s.SendEvent(NewUserNotificationEvent(event))
 		}
 	}
 }