feat: add onMany to BaseEventManager (#25492)

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

web/src/lib/managers/upload-manager.svelte.ts

@@ -6,8 +6,10 @@ class UploadManager {
   mediaTypes = $state<ServerMediaTypesResponseDto>({ image: [], sidecar: [], video: [] });
 
   constructor() {
-    eventManager.on('AppInit', () => this.#loadExtensions());
-    eventManager.on('AuthLogout', () => this.reset());
+    eventManager.onMany({
+      AppInit: () => this.#loadExtensions(),
+      AuthLogout: () => this.reset(),
+    });
   }
 
   reset() {

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() {

web/src/lib/utils/base-event-manager.svelte.ts

@@ -30,6 +30,17 @@ export class BaseEventManager<Events extends EventMap> {
     };
   }
 
+  onMany(subscriptions: { [T in keyof Events]?: EventCallback<Events, T> }) {
+    const cleanups = Object.entries(subscriptions).map(([event, callback]) =>
+      this.on(event as keyof Events, callback as EventCallback<Events, keyof Events>),
+    );
+    return () => {
+      for (const cleanup of cleanups) {
+        cleanup();
+      }
+    };
+  }
+
   emit<T extends keyof Events>(event: T, ...params: Events[T]) {
     const listeners = this.getListeners(event);
     for (const listener of listeners) {