Added ability to set colead.

frontend/src/pages/Volunteers.svelte

@@ -87,6 +87,15 @@
     }
   }
 
+  async function toggleLead(v) {
+    try {
+      const updated = await api.volunteers.update(v.id, { ...v, is_lead: !v.is_lead })
+      await db.volunteers.put(updated)
+    } catch (err) {
+      error = err.message
+    }
+  }
+
   async function deleteVolunteer(v) {
     if (!confirm(`Delete volunteer "${v.name}"?`)) return
     try {
@@ -243,6 +252,10 @@
               </td>
               {#if canManage}
                 <td>
+                  <button class="btn btn-ghost btn-sm" onclick={() => toggleLead(v)}
+                    title={v.is_lead ? 'Remove lead' : 'Mark as lead'}>
+                    {v.is_lead ? 'Unlead' : 'Lead'}
+                  </button>
                   <button class="btn btn-danger btn-sm" onclick={() => deleteVolunteer(v)}>Delete</button>
                 </td>
               {/if}