v0.0.3 - Semantic Fidelity & Textual Notation Improvements

Major improvements to SysML v2 specification compliance.

Highlights:
- Implicit parameter redefinition (by position)
- Reference subsetting member contribution (perform, references)
- Complete textual notation for history/entry/exit/defer
- If/else branch namespaces
- Flow payload declaration
- Homebrew distribution for macOS
- 51 execution conformance tests + 5 gRPC tests
- 950+ tests passing

See release notes for complete details.