Grafana: line charts in MG red

The tiles, bar charts and route map were already MG red; the line
charts still used Grafana's default palette. Now the first line of a
pair is MG red (#E0424C) and the second light red (#FF9A9E), as in
the app; the tyre chart adds deep (#A8323A) and pale (#FFD0D2) red.
Covers SoC/range, power/speed, voltage/current, tyre pressures and the
charging curve. Checked by rendering the Live and Charging dashboards.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QLJfZQZeAKAwSqViTmLzki

k8s/grafana/dashboards/charging.json

@@ -499,6 +499,36 @@
                 "value": "right"
               }
             ]
+          },
+          {
+            "matcher": {
+              "id": "byName",
+              "options": "powerKw"
+            },
+            "properties": [
+              {
+                "id": "color",
+                "value": {
+                  "mode": "fixed",
+                  "fixedColor": "#E0424C"
+                }
+              }
+            ]
+          },
+          {
+            "matcher": {
+              "id": "byName",
+              "options": "socPercent"
+            },
+            "properties": [
+              {
+                "id": "color",
+                "value": {
+                  "mode": "fixed",
+                  "fixedColor": "#FF9A9E"
+                }
+              }
+            ]
           }
         ]
       },