Fix thread search suggestions: navigate on click, fix duplicate ID

- Add explicit click handler on suggestions so clicking navigates
  to the existing thread instead of interacting with the form
- Fix duplicate id="thread_title_input" in forms.j2 edit macro
  (renamed to edit_title_input to avoid conflict with create form)

remarkbox/static/js/custom.js

@@ -147,6 +147,16 @@ function initThreadTitleTypeahead() {
         }, 400);
     });
 
+    // Clicking a suggestion navigates to that thread.
+    suggestionsDiv.addEventListener('click', function(e) {
+        var link = e.target.closest('.suggestion-item');
+        if (link && link.href) {
+            e.preventDefault();
+            e.stopPropagation();
+            window.location.href = link.href;
+        }
+    });
+
     // Hide suggestions when clicking outside.
     document.addEventListener('click', function(e) {
         if (e.target !== titleInput && !suggestionsDiv.contains(e.target)) {

remarkbox/templates/snippets/forms.j2

@@ -49,7 +49,7 @@
     {% if node.title %}
     <input
         name        = "thread_title"
-        id          = "thread_title_input"
+        id          = "edit_title_input"
         class       = "common-text-input"
         value       = "{{ node.title }}"
         placeholder = "Descriptive title"