feat: show backend optimization progress

src/app/api/jobs/[jobId]/progress/route.ts

@@ -0,0 +1,18 @@
+import { NextResponse } from "next/server";
+
+import { requireApiAccess } from "../../../../../lib/api/auth";
+import { getWorkflowProgress } from "../../../../../lib/workflow/progress-store";
+
+interface RouteContext {
+  params: Promise<{ jobId: string }>;
+}
+
+export async function GET(request: Request, context: RouteContext) {
+  const access = requireApiAccess(request);
+  if (!access.ok) {
+    return access.response;
+  }
+
+  const { jobId } = await context.params;
+  return NextResponse.json({ progress: getWorkflowProgress(jobId) });
+}