Port SysML→GDS prototype from unity-GDS-experiments to gds-core

[rororowyourboat]

Summary

Port the working SysML v2 → GDS pipeline from unity-GDS-experiments into gds-core as the foundation for the gds-sysml package (#188).

What exists in unity-GDS-experiments

File	Lines	What it does
sysml_parser.py	649	Regex-based SysML v2 parser with @gds* annotation extraction
sysml_to_rdf.py	387	SysMLModel → rdflib.Graph using gds-core ontology
spec_builder.py	839	End-to-end lifecycle: parse → RDF → GDSSpec → compile → verify
sysml_validator.py	250+	Structural validation for parsed SysML models
simple_satellite.sysml	589	Reference model: 19 part defs, 80+ @gds* annotations
test_rdf_roundtrip.py	146	37 tests: RDF graph structure, roundtrip fidelity, 29+6 verification
test_spec_builder.py	216	21 tests: block structure, semantic checks, structural annotations

Total: 194 tests passing, pipeline produces a GDSSpec with 7 blocks, 20 state variables, 14 parameters.

What needs to change during port

1. Namespace: gds_lifecycle.sysml_parser → gds_sysml.parser.regex
2. RDF construction: Replace imperative triple building in sysml_to_rdf.py with SPARQL CONSTRUCT queries (Research spike: OSLC SysML v2 → GDS ontology SPARQL CONSTRUCT mapping #189) — or keep as initial implementation and refactor later
3. Remove satellite-specific hardcoding: sysml_to_rdf.py has canonical state variable and parameter lists (lines 54-67) specific to the satellite model. The generic pipeline should derive these from @gds* metadata only.
4. Unit mapping table: The unit→TypeDef mapping (lines 34-51 in sysml_to_rdf.py) should be configurable, not hardcoded
5. Package structure: Follow gds-owl's structure (export.py, import_.py, _namespace.py)
6. Test fixtures: Extract simple_satellite.sysml as a test fixture, add at least one non-satellite model

Acceptance Criteria

• All 37 RDF roundtrip tests pass in new location
• All 21 spec builder tests pass
• simple_satellite.sysml produces identical GDSSpec (29/29 + 6/6 checks)
• No satellite-specific hardcoding in the generic pipeline
• Package installable as gds-sysml in workspace

Dependencies

• gds-sysml: SysML v2 bridge package via OSLC RDF vocabulary #188 (gds-sysml package design)
• gds-owl ≥ current version (for graph_to_spec)
• gds-framework ≥ 0.3.0 (for structural annotations: TransitionSignature, AdmissibleInputConstraint, StateMetric)