fix(update): concurrent apply reads as progress, not failure; idle-IO extraction

"Another update operation is already running" surfaced as a scary
failure while the update was in fact applying fine (OptiPlex, v1.7.118
rollout). The apply path now joins the in-flight install — same
overlay, same wait-for-new-version polling — and a concurrent download
attempt shows a calm in-progress note (EN+ES strings added). The
backend's tarball extractions run under ionice -c3 nice -n10 so a
200MB update can't starve podman/status calls into multi-minute
timeouts on small disks.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/views/SystemUpdate.vue

@@ -978,6 +978,11 @@ async function downloadUpdate() {
       updateInProgress.value = false
       await loadStatus()
       showStatus(t('systemUpdate.upToDateMessage'))
+    } else if (/already running/i.test(msg)) {
+      // A download/apply is already in flight (auto-updater or another tab) —
+      // that's progress, not failure. Re-sync state and say so calmly.
+      await loadStatus()
+      showStatus(t('systemUpdate.downloadInProgress'))
     } else {
       // A failed download is NOT a staged update — return the UI to the
       // Download button so the user can retry, instead of stranding them on
@@ -1065,6 +1070,20 @@ async function applyUpdate() {
       setTimeout(() => window.location.reload(), 3000)
     }
   } catch (e) {
+    // "Another update operation is already running" is NOT a failure — an
+    // apply (or the auto-updater) is already doing the work. Presenting it
+    // as an error made a successfully-updating node look broken (OptiPlex,
+    // v1.7.118 rollout). Join the in-flight apply instead: same overlay,
+    // same wait-for-new-version polling.
+    if (/already running/i.test(errorMessage(e))) {
+      applying.value = false
+      if (target) {
+        startInstallOverlay(target)
+      } else {
+        showStatus(t('systemUpdate.applyInProgress'))
+      }
+      return
+    }
     showStatus(t('systemUpdate.applyFailed'), true)
     if (import.meta.env.DEV) console.warn('Apply failed', e)
     applying.value = false