Phase 3: Health Check + Task Queue for Agent Tab

Backend: _get_agent_health() with CPU/Memory/Threads from ps, get_agent_tasks() reads tasks.json. API: GET /api/agents/{id}/health + /tasks. Frontend: Health metrics block in Overview tab (CPU, Memory bar, Threads), Tasks tab with status-colored task list.

static/style.css

@@ -1668,3 +1668,47 @@ body.resizing{user-select:none;cursor:col-resize;}
   gap: 8px;
   flex-wrap: wrap;
 }
+
+.health-metrics .agent-info-row {
+  padding: 4px 0;
+}
+
+.health-bar {
+  height: 4px;
+  background: var(--border);
+  border-radius: 2px;
+  margin-top: 4px;
+  width: 100px;
+}
+
+.health-bar-fill {
+  height: 4px;
+  background: #4caf50;
+  border-radius: 2px;
+  transition: width 0.3s;
+}
+
+.task-list {
+  padding: 8px;
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
+.task-row {
+  display: flex;
+  align-items: flex-start;
+  gap: 10px;
+  padding: 8px 10px;
+  border-radius: 8px;
+  background: var(--card-bg);
+  border: 1px solid var(--border);
+}
+
+.task-status-dot {
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  flex-shrink: 0;
+  margin-top: 4px;
+}