scientific(topic): bind fitted topic-basis identity to owner-issued reference fit #666

Finding

#663 added FittedTopicBasisIdentity, but its public constructor still accepts an arbitrary &ReferenceTopicModel plus a caller-supplied vocabulary width. ReferenceTopicModel is intentionally inspectable/mutable in tests, so a downstream caller can manufacture a fit-local basis identity from a detached or hand-mutated model that was not minted together with the admitted estimator input/configuration.

#665 now provides the correct owner-issued nominal aggregate, ReferenceTopicFit, which can only be created by executing the CPU reference estimator over the retained ReferenceTopicInput and ReferenceTopicModelConfig. The fitted-topic basis public boundary should consume that aggregate rather than a detached model/width pair.

This is not Evidence/source provenance (#658) and does not authorize release projection by itself. It is a numerical-owner authority repair required before #663 can claim owner-issued topic coordinates.

Required RED

Use an actual converged ReferenceTopicFit and require a public FittedTopicBasisIdentity::from_bound_fit(&fit) path. The existing detached from_model(model, vocabulary_size) path must cease to be public API; malformed/model-only tests may remain inside the owner module as private validation tests.

Positive acceptance:

• repeated projection from the same owner-issued fit is bit/digest deterministic;
• topic row identities remain content-bound and the enclosing basis remains order-sensitive;
• the vocabulary width comes from the retained admitted input, not a caller integer.

Negative/authority acceptance:

• no public constructor accepts a detached ReferenceTopicModel + vocabulary width;
• malformed and duplicate fitted-topic rows still fail closed inside owner tests;
• no topic reordering, semantic naming, LLM interpretation, source/vocabulary provenance claim, or covariance transformation is introduced.

Boundary

• scientific(topic): bind reference fit results to the admitted estimator input #665 owns fit ↔ admitted-input/config integrity.
• release(topic): bind topic-index coordinates to the fitted topic basis #663 owns release-level topic-basis coordinate binding.
• release(provenance): bind topic-lineage input to owner-issued source snapshot evidence #658/feat(evidence): own immutable source snapshot receipts #527 own source/vocabulary provenance.
• This issue owns only the fit-local public constructor authority for FittedTopicBasisIdentity.

Keep #639 Draft. No source copy, detached digest promotion, force push, destructive rebase, self-approval, or gate weakening.

Refs #638 #639 #658 #663 #665 ADR 0012.