Closes #7642

/claim #7642

Adds two new service templates for SurrealDB:

• surrealdb — standalone mode using SurrealKV (the default first-party storage engine in v2). Persistent volume at /data, auto-generated credentials via SERVICE_USER/PASSWORD_SURREALDB, healthcheck on /health.
• surrealdb-with-tikv — distributed mode backed by a TiKV cluster (PD + TiKV + SurrealDB). PD gets a healthcheck, TiKV depends on PD being healthy, and SurrealDB waits for both before starting.

Both templates use surrealdb/surrealdb:v2, expose port 8000, and follow the existing coolify service template conventions.

Also added a placeholder SVG logo and regenerated both service-templates.json and service-templates-latest.json.