Remove residual Wright-owned OPY IR/lowering shim after owner cutover

[Teakowa]

Goal

Finish the residual cleanup left after the source-language ownership cutover so Wright no longer carries OPY-owner IR/lowering implementation or Workshop re-export shims that are now owned by opy-rs / workshop-rs.

Current reality

wright#228 completed the functional owner cutover and Wright now consumes released OPY/DEL owner contracts. The old crates/wright-workshop adapter is already gone from current main.

However, crates/wright-ir still exists and its current crate documentation explicitly describes:

• an internal OPY HIR model;
• HIR → Workshop lowering;
• generic IR infrastructure re-exported from workshop-rs;
• these shims as temporary until HIR/lowering extraction to opy-rs.

The original extraction prerequisite is therefore no longer a future blocker: the owner implementation and released consumer boundary exist. What remains is bounded residual cleanup in Wright.

Scope

• Determine which wright-ir items are still consumed by current Wright product/integration code after refactor: complete source-language ownership cutover #228.
• Remove residual OPY HIR/lowering implementation that is now authoritative in opy-rs.
• Remove Workshop-type/infrastructure re-export shims where consumers can use released workshop-rs types directly.
• Retain only Wright-owned integration/tooling types that have an actual current consumer contract; relocate/rename them if needed without reintroducing source-language ownership.
• Preserve existing Wright integration behavior and machine contracts.

Non-goals

• No OPY semantic or lowering changes in Wright.
• No redesign of opy-rs, workshop-rs, provider architecture, or LPP.
• No unrelated IR/framework cleanup.
• No requirement to remove a type solely because its historical name contains ir; ownership and actual consumers decide the boundary.

Acceptance criteria

• Wright contains no authoritative OPY HIR or OPY→Workshop lowering implementation duplicated from opy-rs.
• Wright contains no compatibility-only Workshop adapter/re-export layer when direct released workshop-rs consumption is sufficient.
• Any retained shared/integration types have a concrete Wright-owned consumer purpose and do not duplicate canonical language semantics.
• Existing OPY, DEL, raw Workshop, CLI, embedding, and integration gates remain regression-green.
• No second canonical Workshop or OPY implementation appears.

Readiness

Ready, but not on the semantic critical path. The prerequisite owner cutover is complete; prioritize this only as bounded maintenance after active engine-semantic blockers.