export an open-todos gauge and chart it on the agent dashboard

nix/host-modules/swarm-grafana/dashboards/agents.json

@@ -923,6 +923,80 @@
           }
         }
       },
+      "panel-68": {
+        "kind": "Panel",
+        "spec": {
+          "id": 68,
+          "title": "Open todos by agent",
+          "description": "Open todos in each agent's todo list over time; reminders excluded.",
+          "links": [],
+          "data": {
+            "kind": "QueryGroup",
+            "spec": {
+              "queries": [
+                {
+                  "kind": "PanelQuery",
+                  "spec": {
+                    "query": {
+                      "kind": "DataQuery",
+                      "group": "prometheus",
+                      "version": "v0",
+                      "datasource": {
+                        "name": "@datasourceUid@"
+                      },
+                      "spec": {
+                        "expr": "sum by (agent) ({__name__=\"hyperhive.agent.todos.open\", hive=~\"$hive\", agent=~\"$agent\"})",
+                        "legendFormat": "{{agent}}"
+                      }
+                    },
+                    "refId": "A",
+                    "hidden": false
+                  }
+                }
+              ],
+              "transformations": [],
+              "queryOptions": {}
+            }
+          },
+          "vizConfig": {
+            "kind": "VizConfig",
+            "group": "timeseries",
+            "version": "",
+            "spec": {
+              "options": {
+                "legend": {
+                  "calcs": [],
+                  "displayMode": "list",
+                  "placement": "bottom",
+                  "showLegend": true
+                },
+                "tooltip": {
+                  "mode": "multi",
+                  "sort": "desc"
+                }
+              },
+              "fieldConfig": {
+                "defaults": {
+                  "unit": "short",
+                  "decimals": 0,
+                  "color": {
+                    "mode": "palette-classic"
+                  },
+                  "custom": {
+                    "axisSoftMin": 0,
+                    "drawStyle": "line",
+                    "fillOpacity": 0,
+                    "lineWidth": 1,
+                    "showPoints": "never",
+                    "spanNulls": false
+                  }
+                },
+                "overrides": []
+              }
+            }
+          }
+        }
+      },
       "panel-4": {
         "kind": "Panel",
         "spec": {
@@ -2913,6 +2987,19 @@
                           "name": "panel-34"
                         }
                       }
+                    },
+                    {
+                      "kind": "GridLayoutItem",
+                      "spec": {
+                        "x": 0,
+                        "y": 31,
+                        "width": 24,
+                        "height": 8,
+                        "element": {
+                          "kind": "ElementReference",
+                          "name": "panel-68"
+                        }
+                      }
                     }
                   ]
                 }