Grafana: map zooms to the route; plain hyphens in titles

- "Where the car was" fits the route again: in Grafana's fit view the
  zoom value is the maximum zoom, and 6 held it at country level. Now
  15 with 10 % padding. Checked by rendering the Live dashboard with a
  simulated 10 km drive.
- Dashboard titles use "-" instead of an em dash: "MG4 - Live",
  "MG4 - Consumption", "MG4 - Charging".
- SPECS.md: Grafana keeps its state in SQLite on its PVC, which is why
  it runs as one replica with Recreate; high availability needs
  PostgreSQL or MySQL first.

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

k8s/grafana/dashboards/charging.json

@@ -1,6 +1,6 @@
 {
   "uid": "mg4-charging",
-  "title": "MG4 — Charging",
+  "title": "MG4 - Charging",
   "description": "DC charging sessions metered by the car. Prices in euro, as entered in the car's Charging tab.",
   "tags": [
     "mg4"