Cache DOM elements and add no-op guard in status poller

Cache #swap-status textarea and .loader-text once before the interval
instead of re-querying the DOM on every 300ms tick. Track lastText to
skip the DOM write when the status text hasn't changed.

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

static/wire_outputs.js

@@ -362,12 +362,16 @@ function init() {
 
     function startStatusPolling() {
         stopStatusPolling();
+        const statusEl   = document.querySelector('#swap-status textarea');
+        const loaderText = document.querySelector('.loader-text');
+        if (!statusEl || !loaderText) return;
+        let lastText = '';
         _statusPoller = setInterval(() => {
-            const el = document.querySelector('#swap-status textarea');
-            if (!el) return;
-            const text = el.value.trim();
-            const loaderText = document.querySelector('.loader-text');
-            if (loaderText && text) loaderText.textContent = text;
+            const text = statusEl.value.trim();
+            if (text && text !== lastText) {
+                lastText = text;
+                loaderText.textContent = text;
+            }
         }, 300);
     }