fix(telemetry): set units, axis labels, and readable legends on close-time panels

Apply the dashboard guidelines to the five close-time panels:

- Axis labels (Title Case) on every panel: "Close Time (Ripple
  Seconds)" for the value panels, "Count / Milliseconds" for vote
  bins/resolution, "Rounds in Window" for the count panels.
- Human-readable legends with the dimension in brackets per the legend
  convention: "Raw Close Time [{{resource.service.instance.id}}]",
  "Effective Close Time [...]", "Resolution Direction
  [{{span.resolution_direction}}]", "{{span.close_time_vote_bins}} Vote
  Bins" — replacing the bare label tokens.
- Unit "none" (plain number): the close-time values are Ripple-epoch
  seconds and TraceQL metrics cannot offset them to a wall-clock unit,
  and the others are counts/ms on a shared axis.

Verified rendered values against raw spans: close times ~833,998,8xx,
resolution 10000 ms, vote bins 1/2/3 — all correct.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker/telemetry/grafana/dashboards/consensus-health.json

@@ -406,7 +406,8 @@
           "custom": {
             "drawStyle": "points",
             "pointSize": 6,
-            "showPoints": "always"
+            "showPoints": "always",
+            "axisLabel": "Close Time (Ripple Seconds)"
           }
         },
         "overrides": []
@@ -430,7 +431,7 @@
           },
           "queryType": "traceql",
           "query": "{name=\"consensus.accept.apply\" && resource.service.instance.id=~\"$node\"} | avg_over_time(span.close_time_self) by (resource.service.instance.id)",
-          "legendFormat": "{{resource.service.instance.id}}",
+          "legendFormat": "Raw Close Time [{{resource.service.instance.id}}]",
           "refId": "A"
         }
       ]
@@ -451,7 +452,8 @@
           "custom": {
             "drawStyle": "points",
             "pointSize": 6,
-            "showPoints": "always"
+            "showPoints": "always",
+            "axisLabel": "Close Time (Ripple Seconds)"
           }
         },
         "overrides": []
@@ -475,7 +477,7 @@
           },
           "queryType": "traceql",
           "query": "{name=\"consensus.accept.apply\" && resource.service.instance.id=~\"$node\"} | avg_over_time(span.close_time) by (resource.service.instance.id)",
-          "legendFormat": "{{resource.service.instance.id}}",
+          "legendFormat": "Effective Close Time [{{resource.service.instance.id}}]",
           "refId": "A"
         }
       ]
@@ -496,8 +498,10 @@
             "drawStyle": "line",
             "lineInterpolation": "stepAfter",
             "pointSize": 5,
-            "showPoints": "auto"
-          }
+            "showPoints": "auto",
+            "axisLabel": "Count / Milliseconds"
+          },
+          "unit": "none"
         },
         "overrides": [
           {
@@ -584,8 +588,10 @@
             "drawStyle": "bars",
             "fillOpacity": 40,
             "pointSize": 5,
-            "showPoints": "auto"
-          }
+            "showPoints": "auto",
+            "axisLabel": "Rounds in Window"
+          },
+          "unit": "none"
         },
         "overrides": []
       },
@@ -608,7 +614,7 @@
           },
           "queryType": "traceql",
           "query": "{name=\"consensus.accept.apply\" && resource.service.instance.id=~\"$node\" && span.resolution_direction=~\"$resolution_direction\"} | count_over_time() by (span.resolution_direction)",
-          "legendFormat": "{{span.resolution_direction}}",
+          "legendFormat": "Resolution Direction [{{span.resolution_direction}}]",
           "refId": "A"
         }
       ]
@@ -625,9 +631,10 @@
       },
       "fieldConfig": {
         "defaults": {
-          "unit": "short",
+          "unit": "none",
           "custom": {
-            "fillOpacity": 60
+            "fillOpacity": 60,
+            "axisLabel": "Rounds in Window"
           }
         },
         "overrides": []
@@ -654,7 +661,7 @@
           },
           "queryType": "traceql",
           "query": "{name=\"consensus.accept.apply\" && resource.service.instance.id=~\"$node\"} | count_over_time() by (span.close_time_vote_bins)",
-          "legendFormat": "{{span.close_time_vote_bins}} bins",
+          "legendFormat": "{{span.close_time_vote_bins}} Vote Bins",
           "refId": "A"
         }
       ]