finally fix race conditions for file progress

uses sse to deliver updates

app/services/ProgressManager.ts

@@ -0,0 +1,45 @@
+import { EventEmitter } from 'events';
+
+export interface ProgressUpdate {
+    filename: string;
+    progress: number;
+    status: 'processing' | 'complete' | 'error';
+    message?: string;
+}
+
+class ProgressManager {
+    private static instance: ProgressManager;
+    private emitter: EventEmitter;
+    private activeJobs: Map<string, ProgressUpdate>;
+
+    private constructor() {
+        this.emitter = new EventEmitter();
+        this.activeJobs = new Map();
+    }
+
+    static getInstance(): ProgressManager {
+        if (!ProgressManager.instance) {
+            ProgressManager.instance = new ProgressManager();
+        }
+        return ProgressManager.instance;
+    }
+
+    updateProgress(update: ProgressUpdate) {
+        this.activeJobs.set(update.filename, update);
+        this.emitter.emit('progress', update);
+    }
+
+    subscribeToUpdates(callback: (update: ProgressUpdate) => void) {
+        this.emitter.on('progress', callback);
+    }
+
+    unsubscribeFromUpdates(callback: (update: ProgressUpdate) => void) {
+        this.emitter.off('progress', callback);
+    }
+
+    getJobStatus(filename: string): ProgressUpdate | undefined {
+        return this.activeJobs.get(filename);
+    }
+}
+
+export const progressManager = ProgressManager.getInstance();