fix(service): use FQDN instead of URL for Grafana GF_SERVER_DOMAIN

GF_SERVER_DOMAIN expects a bare hostname (e.g. grafana.example.com) but
was set to SERVICE_URL_GRAFANA which includes the protocol
(https://grafana.example.com). This mismatch can cause Grafana to fail
to load its application files when deployed behind Coolify's proxy.

Changed to SERVICE_FQDN_GRAFANA which provides just the hostname. Applied
the fix to both grafana.yaml and grafana-with-postgresql.yaml templates.

Fixes #5307

templates/compose/grafana-with-postgresql.yaml

@@ -11,7 +11,7 @@ services:
     environment:
       - SERVICE_URL_GRAFANA_3000
       - GF_SERVER_ROOT_URL=${SERVICE_URL_GRAFANA}
-      - GF_SERVER_DOMAIN=${SERVICE_URL_GRAFANA}
+      - GF_SERVER_DOMAIN=${SERVICE_FQDN_GRAFANA}
       - GF_SECURITY_ADMIN_PASSWORD=${SERVICE_PASSWORD_GRAFANA}
       - GF_DATABASE_TYPE=postgres
       - GF_DATABASE_HOST=postgresql

templates/compose/grafana.yaml

@@ -11,7 +11,7 @@ services:
     environment:
       - SERVICE_URL_GRAFANA_3000
       - GF_SERVER_ROOT_URL=${SERVICE_URL_GRAFANA}
-      - GF_SERVER_DOMAIN=${SERVICE_URL_GRAFANA}
+      - GF_SERVER_DOMAIN=${SERVICE_FQDN_GRAFANA}
       - GF_SECURITY_ADMIN_PASSWORD=${SERVICE_PASSWORD_GRAFANA}
     volumes:
       - grafana-data:/var/lib/grafana