fix(migrate): an untyped property follows its tool's kind marker; unmarked, it is an attribute, or a part when composite

[devin-ai-integration]

What and why

The SysML v1 migrator wrote every property without a type as ref x; (featureKeyword returned ref whenever t == nil). That ignored MagicDraw's property-kind markers — a «ValueProperty» with no type came out as ref x { /* applied stereotype «ValueProperty» */ }, the marker written as an applied stereotype because the generated keyword did not represent it — and it made plain classes whose attributes carry no type (a filename, a capture date) look like reference parts in a Cameo/CATIA model browser.

An untyped property is now written by untypedKeyword:

• the usage its marker names — «ValueProperty» attribute, «PartProperty» part, «SharedProperty»/«ReferenceProperty» ref, «ConstraintProperty» constraint — with the marker omitted, as it already is on typed properties (markedPropertyKind and isPropertyKindMarker share one propertyKindMarker reading);
• a ref typed by its default individual, as before;
• otherwise a part when its aggregation is composite and an attribute otherwise, each reported approximated with a note saying so.

Typed properties are unchanged.

Specification basis

OMG SysML v1 to v2 Transformation mapping model, PropertyUntyped_Mapping (UML4SysML::Classification), which maps an untyped property to a ReferenceUsage. This change deliberately departs from it, so the census row moves from faithful to approximate with the reason recorded in docs/project/sysml-v1-transformation-census-baseline.json; docs/reference/sysml-v1-migration.md gains the two rows (marked / unmarked untyped property).

How it was verified

• tests/migrate/testdata/xmi/property_markers.xmi gains seven untyped properties (one per marker, one unmarked scalar, one unmarked composite); TestPropertyKindMarkersAreNotWritten pins attribute load;, part trailer;, ref depot;, ref driver;, constraint rule;, attribute color;, part chassis;, the marked ones mapped and the unmarked ones approximated with their notes, and that no marker is written as a stereotype.
• TestUntypedPropertiesAreAttributesInAndOutsideConstraintDefinitions (renamed) and the existing individual-default tests (ref angles : usual; kept) pin the unmarked and individual paths; expectations in relations_test.go, behavior_members_internal_test.go and diagrams_internal_test.go that encoded the old ref moved to attribute; goldens for property_markers, collectors and tool_profiles regenerated and reviewed.
• go build ./..., go vet ./..., gofmt -l . (empty), go test ./... green; go run -C tools ./cmd/transformation-census -check and python3 scripts/changelog.py check pass.

Checklist

• make test and make lint pass locally
• Tests added or updated for the change
• Documentation extended where it already covers the surface (see CONTRIBUTING.md)
• Changelog entry added as changes/unreleased/<slug>.<section>.md, not as an edit to CHANGELOG.md
• baselines regenerated and make docs-counts run if a gate count moved (compliance rows need nothing: the census is counted at docs build)
• No internal work-item labels (waves, slices, F4, K5) in the body, docs, or changelog

Link to Devin session: https://nasa-jpl-demo.devinenterprise.com/sessions/dbff7ccc1454416fb497412e51cf5513
Open in Devin Desktop: https://nasa-jpl-demo.devinenterprise.com/desktop/session/dbff7ccc1454416fb497412e51cf5513?variant=devin
Requested by: @HuiJun

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring