fix: html-router modals and add insta snapshot tests.

Avoid nested forms in the scratchpad editor, centralize modal lifecycle in modal.js, return HTMX partials from archive, and add template compile plus layout snapshots.

html-router/templates/chat/reference_list.html

@@ -1,7 +1,6 @@
 <div class="relative my-2">
-  <button id="references-toggle-{{message.id}}"
-    class="nb-btn btn-xs bg-base-100 hover:bg-base-200 flex items-center"
-    onclick="toggleReferences('{{message.id}}')">
+  <button id="references-toggle-{{message.id}}" data-message-id="{{message.id}}"
+    class="references-toggle nb-btn btn-xs bg-base-100 hover:bg-base-200 flex items-center">
     REFERENCES
     {% include "icons/chevron_icon.html" %}
   </button>
@@ -20,6 +19,19 @@
 </div>
 
 <script>
+  // Register global handlers once; this fragment is re-injected per SSE response.
+  if (!window.__referencesInit) {
+    window.__referencesInit = true;
+
+    document.body.addEventListener('click', function (e) {
+      const btn = e.target.closest('.references-toggle');
+      if (btn) toggleReferences(btn.dataset.messageId);
+    });
+
+    document.addEventListener('DOMContentLoaded', initializeReferenceTooltips);
+    document.body.addEventListener('htmx:afterSwap', initializeReferenceTooltips);
+  }
+
   function toggleReferences(messageId) {
     const refsContent = document.getElementById('references-content-' + messageId);
     const refsList = document.getElementById('references-list-' + messageId);
@@ -56,15 +68,6 @@
     }
   }
 
-  // Initialize portal tooltips
-  document.addEventListener('DOMContentLoaded', function () {
-    initializeReferenceTooltips();
-  });
-
-  document.body.addEventListener('htmx:afterSwap', function () {
-    initializeReferenceTooltips();
-  });
-
   function initializeReferenceTooltips() {
     document.querySelectorAll('.reference-badge-container').forEach(container => {
       if (container.dataset.initialized === 'true') return;
@@ -145,4 +148,7 @@
       container.dataset.initialized = 'true';
     });
   }
+
+  // Initialize any badges present in this freshly injected fragment (idempotent).
+  initializeReferenceTooltips();
 </script>