feat(updates): visual update indicators, progress feedback, settings pull

- Dashboard: update badge (orange) injected lazily into customer Status cell
  after table renders via GET /monitoring/customers/local-update-status
  (local-only Docker inspect, no Hub call on every page load)
- Customer detail Deployment tab: "Update Images" button with spinner,
  shows success/error inline without page reload
- Monitoring Update All: now synchronous + sequential (one customer at a
  time), shows live spinner + per-customer results table on completion
- Settings > Docker Images: "Pull from Docker Hub" button with spinner
  and inline status message
- /monitoring/customers/local-update-status: new lightweight endpoint
  (no network, pure local Docker inspect)
- /monitoring/customers/update-all: removed BackgroundTasks, now awaits
  each customer sequentially and returns detailed per-customer results

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

static/index.html

@@ -634,6 +634,13 @@
                                                         Settings</span></button>
                                             </div>
                                         </form>
+                                        <hr>
+                                        <h6 data-i18n="settings.pullImagesTitle">Pull Latest Images from Docker Hub</h6>
+                                        <p class="text-muted small" data-i18n="settings.pullImagesHint">Downloads the latest versions of all configured NetBird images. After pulling, use Monitoring to update customer containers.</p>
+                                        <button class="btn btn-outline-primary" onclick="pullAllImagesSettings()" id="btn-pull-images-settings">
+                                            <i class="bi bi-cloud-download me-1"></i><span data-i18n="settings.pullImages">Pull from Docker Hub</span>
+                                        </button>
+                                        <span id="pull-images-settings-status" class="ms-2 text-muted small"></span>
                                     </div>
                                 </div>
                             </div>