feat: add SSE event stream for print jobs, implement batch printing in frontend, and update API documentation.

paperless-backend/src/label-print-agent/label-print-agent.service.ts

@@ -1,6 +1,7 @@
 import { Injectable, Logger, NotFoundException, BadRequestException } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { Repository, LessThan, IsNull, Or } from 'typeorm';
+import { Repository, LessThan, IsNull } from 'typeorm';
+import { Subject, Observable } from 'rxjs';
 import { LabelPrintJob } from '../database/entities/label-print-job.entity';
 import { BarcodeTemplate } from '../database/entities/barcode-template.entity';
 import { LabelRendererService } from './label-renderer.service';
@@ -28,6 +29,11 @@ function lockExpiry(): Date {
 @Injectable()
 export class LabelPrintAgentService {
   private readonly logger = new Logger(LabelPrintAgentService.name);
+  private readonly jobCreated$ = new Subject<void>();
+
+  get newJob$(): Observable<void> {
+    return this.jobCreated$.asObservable();
+  }
 
   constructor(
     @InjectRepository(LabelPrintJob)
@@ -85,7 +91,9 @@ export class LabelPrintAgentService {
       LockedByAgent: null,
     });
 
-    return this.jobRepo.save(job);
+    const saved = await this.jobRepo.save(job);
+    this.jobCreated$.next();
+    return saved;
   }
 
   async claimNextJob(agentId: string): Promise<LabelPrintJob | null> {