feat: background task dispatch system with live UI panel

- agent/task_registry.py: file-based JSONL event registry (cross-process)
- agent/task_worker.py: autonomous LLM loop with weather/time/memory/web tools
- agent/dispatch_mcp.py: MCP tool exposing dispatch_task to the main agent
- agent/agent.py: registers dispatch toolset, polls task events → room data
- web: slide-out task panel (FAB button + badge), live step streaming via
  data channel topic 'tasks', status dots (running/completed/failed)
- Dockerfile: copies new task_*.py and dispatch_mcp.py files

The dispatch MCP runs in its own process; events flow through
/tmp/tasks/events.jsonl which the main agent tails every second and
forwards to the browser. Tasks run up to 10 LLM iterations with tool calls.

web/index.html

@@ -64,6 +64,23 @@
         <div class="voice-list" id="voiceList"></div>
     </div>
 
+    <!-- Task panel (background tasks) -->
+    <button id="tasksBtn" class="btn btn-icon tasks-fab" aria-label="Background tasks" title="Background tasks">
+        <svg viewBox="0 0 24 24" width="18" height="18" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="3" width="18" height="18" rx="2"></rect><path d="M9 9h6M9 13h6M9 17h4"></path></svg>
+        <span class="tasks-badge" id="tasksBadge" hidden>0</span>
+    </button>
+    <div class="tasks-panel" id="tasksPanel">
+        <div class="tasks-header">
+            <h2>Background Tasks</h2>
+            <button id="closeTasksBtn" class="btn btn-ghost" aria-label="Close">
+                <svg viewBox="0 0 24 24" width="18" height="18" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"><path d="M18 6 6 18M6 6l12 12"></path></svg>
+            </button>
+        </div>
+        <div class="tasks-list" id="tasksList">
+            <p class="tasks-empty">No tasks yet. Ask Hope to research something.</p>
+        </div>
+    </div>
+
     <script src="livekit-client.umd.js"></script>
     <script src="app.js"></script>
 </body>