Add Grafana iframe embed for Tesla battery chart

Test embed of TeslaMate charge level panel using anonymous auth

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

argocd/manifests/homepage/values.yaml

@@ -73,6 +73,14 @@ config:
                   format:
                     type: bytes
 
+    # Metrics group - Grafana panel embeds
+    - Metrics:
+        - Tesla Battery:
+            widget:
+              type: iframe
+              src: https://grafana.ops.eblu.me/d-solo/WopVO_mgz/tesla-charge-level?orgId=1&from=now-2d&to=now&timezone=browser&var-car_id=1&var-base_url=https://tesla.ops.eblu.me&var-bucket_width=7200&panelId=2&theme=dark
+              classes: h-40
+
   # External bookmarks
   bookmarks:
     - Admin:
@@ -106,6 +114,8 @@ config:
     layout:
       Host Services:
         style: column
+      Metrics:
+        style: row
       Apps:
         style: column
       Observability: