Resolve stale failure stuck on import

app/templates/inboxes.html

@@ -274,16 +274,40 @@
         result.className = "inbox-action-result is-error";
         result.textContent = job.error || "Processing failed.";
         renderDuplicateReports(inboxId, []);
+        progress.classList.remove("is-active", "is-indeterminate");
+        fill.style.width = "0%";
       }
       return running;
     };
 
     const pollJob = async (jobId, inboxId) => {
-      const response = await fetch(`/api/admin/import-jobs/${jobId}`, { credentials: "same-origin" });
-      const job = await response.json();
-      if (renderJob(job, inboxId)) {
-        window.setTimeout(() => pollJob(jobId, inboxId), 2000);
-      } else {
+      try {
+        const response = await fetch(`/api/admin/import-jobs/${jobId}`, { credentials: "same-origin" });
+        if (!response.ok) {
+          throw new Error("Import job status is unavailable.");
+        }
+        const job = await response.json();
+        if (renderJob(job, inboxId)) {
+          window.setTimeout(() => pollJob(jobId, inboxId), 2000);
+        } else {
+          renderInboxStatus(inboxId);
+        }
+      } catch (error) {
+        const result = document.getElementById(`inbox-action-result-${inboxId}`);
+        const progress = document.getElementById(`inbox-progress-${inboxId}`);
+        const fill = progress?.querySelector("span");
+        const buttons = document.querySelectorAll(`.js-inbox-action[data-inbox-id="${inboxId}"]`);
+        buttons.forEach((button) => { button.disabled = false; });
+        if (progress) {
+          progress.classList.remove("is-active", "is-indeterminate");
+        }
+        if (fill) {
+          fill.style.width = "0%";
+        }
+        if (result) {
+          result.className = "inbox-action-result is-error";
+          result.textContent = error.message || "Import job status is unavailable.";
+        }
         renderInboxStatus(inboxId);
       }
     };