feat(ui): Nested task slots in worker dashboard

Backend:
- Add active_tasks array to GET /worker-registry/workers response
- Include task details: role, dispensary, running_seconds, progress

Frontend:
- Show nested task list under each worker with duration
- Display empty slots when worker has capacity
- Update pod visualization to show 3 task slot nodes
- Active slots pulse blue, empty slots gray
- Hover for task details (dispensary, duration, progress)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/routes/worker-registry.ts

@@ -430,9 +430,59 @@ router.get('/workers', async (req: Request, res: Response) => {
       FROM worker_registry
     `);
 
+    // Get active tasks for all workers (for nested task view)
+    const { rows: activeTasks } = await pool.query(`
+      SELECT
+        t.worker_id,
+        t.id as task_id,
+        t.role,
+        t.status as task_status,
+        t.started_at,
+        t.progress,
+        t.progress_message,
+        EXTRACT(EPOCH FROM (NOW() - t.started_at))::int as running_seconds,
+        d.id as dispensary_id,
+        d.name as dispensary_name,
+        d.city as dispensary_city,
+        d.state as dispensary_state
+      FROM worker_tasks t
+      LEFT JOIN dispensaries d ON t.dispensary_id = d.id
+      WHERE t.status IN ('running', 'claimed')
+      ORDER BY t.worker_id, t.started_at
+    `);
+
+    // Group tasks by worker_id
+    const tasksByWorker: Record<string, any[]> = {};
+    for (const task of activeTasks) {
+      if (!tasksByWorker[task.worker_id]) {
+        tasksByWorker[task.worker_id] = [];
+      }
+      tasksByWorker[task.worker_id].push({
+        task_id: task.task_id,
+        role: task.role,
+        status: task.task_status,
+        started_at: task.started_at,
+        running_seconds: task.running_seconds,
+        progress: task.progress,
+        progress_message: task.progress_message,
+        dispensary: task.dispensary_name ? {
+          id: task.dispensary_id,
+          name: task.dispensary_name,
+          city: task.dispensary_city,
+          state: task.dispensary_state,
+        } : null,
+      });
+    }
+
+    // Attach tasks to each worker
+    const workersWithTasks = rows.map((worker: any) => ({
+      ...worker,
+      active_tasks: tasksByWorker[worker.worker_id] || [],
+    }));
+
     res.json({
       success: true,
-      workers: rows,
+      workers: workersWithTasks,
       summary: summary[0]
     });
   } catch (error: any) {