v1.2.0rc1

What's Changed

Registry Refactor with Builder Pattern (#54)

Refactored NodeRegistry and ValueRegistry to support multi-tenancy and explicit, IDE-friendly APIs.

Key changes:

• Three registry implementations: ImmutableRegistry, EagerRegistryBuilder, LazyRegistry
• Freeze-on-first-use lifecycle pattern prevents registration after first access
• Explicit methods (has_name(), get_value_class()) replace dunder overrides for better IDE support
• Fluent builder interface with method chaining
• Independent registry instances enable org-specific custom nodes

Breaking changes:

• value_type_registry → default_value_registry
• in registry → registry.has_name()
• registry[name] → registry.get_value_class(name)

Test coverage: 250 tests passing (61 new registry tests added)

Full Changelog: v1.1.0rc1...v1.2.0rc1