panel: show/hide rules reach a form that arrives in an htmx swap

initShowWhen bound a change listener to each control it found at DOMContentLoaded, so a form swapped in later would have been neither synced nor wired. The rules now listen once on the document and are applied again on htmx:load. No form arrives by a swap today; the roadmap row that recorded the gap is struck.

Checked in a browser on the application form: the rate-limit select toggles the manual and auto fields as before, and a copy of the form put into the page with htmx.swap is synced on arrival and follows its select. go vet and go test ./internal/web/... pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/view/static/panel.js

@@ -153,19 +153,28 @@
 
   function initShowWhen(root) {
     showWhenRules.forEach(function (rule) {
-      root.querySelectorAll(rule.match).forEach(function (control) {
-        syncShowWhen(control);
-        control.addEventListener("change", function () {
-          syncShowWhen(control);
-        });
-      });
+      root.querySelectorAll(rule.match).forEach(syncShowWhen);
     });
   }
 
+  // One listener for the document rather than one per control: a form that
+  // arrives in an htmx swap is covered without being wired up again.
+  document.addEventListener("change", function (ev) {
+    if (ev.target && ev.target.matches) {
+      syncShowWhen(ev.target);
+    }
+  });
+
   document.addEventListener("DOMContentLoaded", function () {
     initShowWhen(document);
   });
 
+  // htmx:load fires for every element htmx puts into the page, so swapped-in
+  // markup starts with its blocks shown or hidden the way a full page does.
+  document.addEventListener("htmx:load", function (ev) {
+    initShowWhen(ev.detail.elt);
+  });
+
   // --- Adaptive monitoring polling ---------------------------------------
   // The four monitoring fragments carry data-poll and hx-trigger="load" for
   // the first fetch only. panel.js schedules the rest: 5 s while the operator