Configurable registry list persisted to config/registries.json. Image pulls try all registries in priority order — if primary fails, fallback registries are attempted automatically. RPC endpoints: registry.list, registry.add, registry.remove, registry.test. Replaces hardcoded fallback logic with extensible registry system. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>