feat(server): Enqueue jobs in bulk (#5974)

* feat(server): Enqueue jobs in bulk

The Job Repository now has a `queueAll` method, that enqueues messages
in bulk (using BullMQ's
[`addBulk`](https://docs.bullmq.io/guide/queues/adding-bulks)),
improving performance when many jobs must be enqueued within the same
operation.

Primary change is in `src/domain/job/job.service.ts`, and other services
have been refactored to use `queueAll` when useful.

As a simple local benchmark, triggering a full thumbnail generation
process over a library of ~1,200 assets and ~350 faces went from
**~600ms** to **~250ms**.

* fix: Review feedback

server/src/domain/user/user.service.ts

@@ -129,12 +129,11 @@ export class UserService {
 
   async handleUserDeleteCheck() {
     const users = await this.userRepository.getDeletedUsers();
-    for (const user of users) {
-      if (this.isReadyForDeletion(user)) {
-        await this.jobRepository.queue({ name: JobName.USER_DELETION, data: { id: user.id } });
-      }
-    }
-
+    await this.jobRepository.queueAll(
+      users.flatMap((user) =>
+        this.isReadyForDeletion(user) ? [{ name: JobName.USER_DELETION, data: { id: user.id } }] : [],
+      ),
+    );
     return true;
   }