feat: add onMany to BaseEventManager (#25492)

Use a map of events instead of array of tuples for better ergonomics.

web/src/lib/stores/memory.store.svelte.ts

@@ -23,8 +23,10 @@ class MemoryStoreSvelte {
   #loading: Promise<void> | undefined;
 
   constructor() {
-    eventManager.on('AuthLogout', () => this.clearCache());
-    eventManager.on('AuthUserLoaded', () => this.initialize());
+    eventManager.onMany({
+      AuthLogout: () => this.clearCache(),
+      AuthUserLoaded: () => this.initialize(),
+    });
   }
 
   ready() {

web/src/lib/stores/notification-manager.svelte.ts

@@ -8,8 +8,10 @@ class NotificationStore {
   notifications = $state<NotificationDto[]>([]);
 
   constructor() {
-    eventManager.on('AuthLogin', () => this.refresh());
-    eventManager.on('AuthLogout', () => this.clear());
+    eventManager.onMany({
+      AuthLogin: () => this.refresh(),
+      AuthLogout: () => this.clear(),
+    });
   }
 
   async refresh() {