feat(tasks): Gemini tool calling for task list management

5 tools: add_task, remove_task, complete_task, get_tasks, clear_completed_tasks
Backend stores tasks in-memory per session. Frontend TaskList component syncs via WS.
Kira can manage tasks via voice or text conversation.

frontend/src/components/TaskList.tsx

@@ -0,0 +1,53 @@
+import { Task } from '../hooks/useConversation';
+
+interface Props {
+  tasks: Task[];
+}
+
+export default function TaskList({ tasks }: Props) {
+  const pending = tasks.filter((t) => !t.completed);
+  const done = tasks.filter((t) => t.completed);
+
+  return (
+    <div className="p-3">
+      <h3 className="text-sm font-bold text-kira-plum mb-2 flex items-center gap-2">
+        <span>✅</span> Tasks
+        {pending.length > 0 && (
+          <span className="text-xs font-normal bg-kira-pink/30 text-kira-plum px-1.5 py-0.5 rounded-full">
+            {pending.length}
+          </span>
+        )}
+      </h3>
+
+      {tasks.length === 0 && (
+        <div className="text-xs text-kira-plum/30 text-center py-4">
+          tell Kira what you need to do!
+        </div>
+      )}
+
+      {pending.length > 0 && (
+        <ul className="space-y-1.5 mb-2">
+          {pending.map((t) => (
+            <li key={t.id} className="flex items-start gap-2 text-sm text-kira-plum">
+              <span className="mt-0.5 shrink-0 w-4 h-4 rounded-full border-2 border-kira-pink/40" />
+              <span className="leading-snug">{t.text}</span>
+            </li>
+          ))}
+        </ul>
+      )}
+
+      {done.length > 0 && (
+        <ul className="space-y-1">
+          {done.map((t) => (
+            <li key={t.id} className="flex items-start gap-2 text-sm text-kira-plum/40 line-through">
+              <span className="mt-0.5 shrink-0 w-4 h-4 rounded-full bg-kira-mint flex items-center justify-center">
+                <span className="text-[8px] text-white">✓</span>
+              </span>
+              <span className="leading-snug">{t.text}</span>
+            </li>
+          ))}
+        </ul>
+      )}
+    </div>
+  );
+}