Agent Skills: ring:migrating-to-lib-systemplane

Migrating Lerian Go services from .env/YAML operational knobs (log levels, feature flags, rate limits, timeouts) to the lib-systemplane hot-reloadable runtime config client, wiring the migration-only make systemplane-ddl pipeline (runtime DDL forbidden in v1.6.0+). Orchestrates an 11-gate cycle dispatching ring:backend-go. Use when adding hot-reloadable config or migrating off v4 systemplane. Skip for non-Go or static-only config.