Spec sync: Clauses 15, 18.3, 18.4, 18.5, 18.7

Goal

The specification records the approved binding contract: what a selected type import binds, how variants resolve in value vs pattern position, how collisions resolve, how pub use re-exports carry the binding, and how construction visibility works.

Implementation Sketch

Author normative clauses (no grammar change): 18.3 (selected type import binding + import-scoped value-position resolution + descriptor parity requirement); 18.4 (construction public-with-type, :: private); 18.5/18.5.1 (pub use carries exactly what the import binds); 18.7 (within-rank collision rule); 15 (variant-pattern type-directed resolution + collision-guard error). Sync .claude/rules/ori-syntax.md. Route through /sync-spec (proposal gate already satisfied: this proposal is approved).

Spec References

Proposal Spec & Grammar Impact (the five clauses); proposals.md (approved proposal authorizes the spec edit).

Work Items

• Author Clause 18.3 / 18.4 / 18.5 / 18.5.1 / 18.7 + Clause 15 normative text per the proposal’s Spec & Grammar Impact; sync ori-syntax.md; via /sync-spec (approved-proposal gate).