Add collapsible sections to public meeting view

Sections on the public meeting page can now be collapsed/expanded with
a click, matching the admin view behavior. State persists via
localStorage using the existing collapsible Stimulus controller.

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

Author: zalepa

app/views/meetings/show.html.erb

@@ -44,12 +44,18 @@
 
   <div class="space-y-6">
     <% @agenda_sections.each do |section| %>
-      <div class="bg-white rounded-lg border border-gray-200 overflow-hidden">
-        <div class="px-6 py-4 bg-gray-50 border-b border-gray-200">
-          <h2 class="font-semibold text-gray-900"><%= section.number %>. <%= section.title %></h2>
-          <span class="text-xs text-gray-500"><%= section.agenda_items.size %> items</span>
-        </div>
+      <div class="bg-white rounded-lg border border-gray-200 overflow-hidden" data-controller="collapsible" data-collapsible-key-value="meeting-<%= @meeting.id %>-section-<%= section.id %>">
+        <button type="button" data-action="click->collapsible#toggle" class="w-full px-6 py-4 bg-gray-50 border-b border-gray-200 flex items-center justify-between cursor-pointer hover:bg-gray-100 transition-colors text-left">
+          <div>
+            <h2 class="font-semibold text-gray-900"><%= section.number %>. <%= section.title %></h2>
+            <span class="text-xs text-gray-500"><%= section.agenda_items.size %> items</span>
+          </div>
+          <svg data-collapsible-target="icon" xmlns="http://www.w3.org/2000/svg" class="h-5 w-5 text-gray-400 transition-transform duration-200 flex-shrink-0 ml-2" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.5">
+            <path stroke-linecap="round" stroke-linejoin="round" d="M19.5 8.25l-7.5 7.5-7.5-7.5" />
+          </svg>
+        </button>
 
+        <div data-collapsible-target="content">
         <% if section.agenda_items.any? %>
           <ul class="divide-y divide-gray-100">
             <% section.agenda_items.each do |item| %>
@@ -98,6 +104,7 @@
             <% end %>
           </ul>
         <% end %>
+        </div>
       </div>
     <% end %>
   </div>