fix(semantics): subset the base feature of a usage kind and derive its type from it

[devin-ai-integration]

What and why

Empties the "Decisions to Reassess" table of docs/project/spec-compliance.md. Both rows recorded a workaround whose premise no longer holds:

• Base features. semantics/implicit.go implicitUsageBases named the stdlib base definition of each usage kind (Parts::Part, Actions::Action, …) because library records once carried no specialization edges, so the base feature would have been a dead end for member lookup. The records have carried Supers for a while (libs/record.go factRecord.Supers → symbols.LibraryFacts.Supers → Model.recordedSupertypes), so the table now names the base feature the spec names (Parts::parts, Items::items, Actions::actions, Connections::binaryConnections for a two-ended connection, …). A SysML usage now implicitly subsets that feature — implicitUsageBaseFeature, a member contributor and implicit general beside the KerML implicitKerMLFeatureBase, never a DirectSupertypes entry — and its type is derived from it (baseFeatureTypes: the feature's declared types plus those of the features it subsets, most-specific kept, KerML Feature::type). kindBaseDefinitionFQNs keeps KindBaseFQNs, computeImplicitBases and the suppression rule (declaredGeneralizationReaches) working on definitions, so the effective typing is unchanged for every kind except a two-ended connection/interface usage, which now derives {Connection, BinaryLinkObject} from binaryConnections as the library states (definitions with two ends still specialize BinaryConnection/BinaryInterface). Member lookup through the feature works: Parts::parts reaches Part and items through the recorded edges.
• Parameter order of a library-indexed behavior. The row assumed a cached library symbol has no parsed AST for ownedParameters to read. It does: the on-disk record path re-parses every library document and the embedded snapshot restores Symbol.Decl, so positional redefinition already holds on every load path. No IndexRecord change and no format bump is needed; a test now locks the three paths.

The libs/loader.go recordEntries the first row pointed at no longer exists; the edges live in record.go.

Specification basis

SysML v2 §7 — each library package states the base feature of its usage kind (Parts::parts "is the base feature of all PartUsages", Connections::binaryConnections "of all binary ConnectionUsages", …); KerML 8.3.3.3 (Feature::type through subsetting); KerML 7.4.7.3 / SysML v2 7.17.2 (positional parameter redefinition). Rows moved: "Features of the stdlib base type of an untyped usage" ⚠️ → ✅; the untyped-connector row names the base features; both "Decisions to Reassess" rows removed.

How it was verified

• New: model/implicit_typing_test.go TestImplicitUsageBaseTypes now asserts, per kind, both the derived definition and the base feature among ImplicitGenerals; TestUsageBaseFeatureSuppressionFollowsDeclaredChain (part p : Vehicle keeps parts, part p :> q with q a part does not); a semantics test asserts the derived definitions for every table entry and both binary features (binaryConnections → [Connection, BinaryLinkObject]); libs/loader_cache_test.go TestLibraryBehaviorParametersRedefinedByPosition (cold load, warm disk cache, embedded snapshot).
• Stand-in libraries in semantics/implicit_test.go gained the base features the real library has; no assertion weakened.
• go build ./..., go vet ./..., gofmt -l . empty, go test -count=1 ./..., make lint, python3 scripts/check-doc-ids.py, python3 scripts/changelog.py check.
• Corpus gates with corpora downloaded (OPENSYSML_REQUIRE_TRAINING_CORPUS=1 OPENSYSML_REQUIRE_PILOT_CORPORA=1 go test -count=1 ./tests/corpus -run 'TestTrainingExamples|TestPilotCorpora'): no movement. Pilot library identity gate (OPENSYSML_REQUIRE_PILOT_LIBRARY_XMI=1 go test -count=1 ./tests/identity -run TestPilotLibraryXMI): passes.
• internal/workspace/libs/stdlib.snapshot regenerated (derived supertypes of the two binary base features changed; format version unchanged).

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

[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