feat(ui): "Republish all" button on the admin Settings card

Surfaces the POST /republish-all endpoint added in the previous
commit. Lives in the existing admin-gated Settings card on the
events extension landing page, so the LNbits operator can trigger
the migration without curl + access tokens.

Confirm dialog before firing (the endpoint emits one Nostr event
per approved row, fine to retry but worth a click of friction).
Notification shows the republished/total count on success.

Self-closing tags expanded per the LNbits UMD rule
(webapp CLAUDE.md > LNbits + Quasar UMD gotchas) — q-separator
and q-btn would silently nest wrong otherwise.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

static/js/index.vue

@@ -15,6 +15,28 @@
               ></q-toggle>
             </div>
           </div>
+          <q-separator class="q-my-md"></q-separator>
+          <div class="row items-center justify-between">
+            <div class="col">
+              <span class="text-subtitle2">Republish to Nostr</span>
+              <div class="text-caption text-grey-7" style="color: #aaa">
+                Re-emit every approved event so connected clients pick
+                up the latest tag set. Useful after the extension
+                publisher changes (e.g. new tickets_* tags) so existing
+                events don't need a per-event edit.
+              </div>
+            </div>
+            <div class="col-auto">
+              <q-btn
+                outline
+                color="primary"
+                icon="cloud_upload"
+                label="Republish all"
+                :loading="republishing"
+                @click="republishAllEvents"
+              ></q-btn>
+            </div>
+          </div>
         </q-card-section>
       </q-card>