Integrate OPY lowering and end-to-end compatibility with workshop-rs

[Teakowa]

Parent: #1

Goal

Connect the completed OPY semantic implementation to canonical workshop-rs semantics and finish the Workshop-dependent parts of OverPy compiler compatibility.

Current readiness

The independent source-language implementation, integration boundary, dependency rebaseline, program-structure lowering, non-control-flow lowering, and control-flow lowering are complete.

Completed compiler slices:

• Establish the versioned OPY-to-Workshop integration boundary #35 — versioned OPY→Workshop integration boundary
• Lower OPY program structure into canonical Workshop WIR #40 — program-structure lowering
• [integration] Rebaseline opy-compiler on current workshop-rs release #52 — rebaseline opy-compiler on the published Workshop contract
• Lower OPY assignment and expression primitives into canonical Workshop WIR #46 — assignment and expression primitives
• Lower OPY control flow into canonical Workshop WIR with oracle evidence #47 — control flow, merged via PR feat(opy-compiler): lower control flow into canonical WIR #61 against workshop-rs 0.1.11
• Lower OPY statements and expressions into canonical Workshop WIR #41 — statements and expressions acceptance gate

The durable dependency direction remains:

OPY source -> parse/preprocess -> semantic resolution/HIR -> opy-compiler -> workshop-rs WIR -> Workshop text

Active execution roadmap

• Lower the declared OPY semantic surface into canonical Workshop WIR #36 — semantic lowering gate
  • Lower OPY statements and expressions into canonical Workshop WIR #41 — statements and expressions
  • Close catalog-backed OPY lowering and corpus evidence #42 — catalog-backed builtin/member/enum semantics and corpus closure (active edge)
• Integrate Workshop-dependent settings, locale, directive, and hook behavior #37 — settings, locale, backend directive/optimizer effects, and post-compile hooks
• Expose OPY compilation and close the end-to-end compatibility gate #38 — versioned compile contract, public library/CLI compile surface, and final end-to-end corpus gate

Current primary order:

#42 → close #36 → #37 → #38 → close #8

Separate/non-gating lanes:

• [design] Re-evaluate Workshop → OPY reconstruction scope after workshop-rs rebaseline #53 — scoped Workshop→OPY reconstruction design.
• Track OverPy null-initializer default semantics #58/Add bounded OverPy increment and decrement assignment support #59/Define bounded multidimensional indexed-assignment lowering #60/Support player-variable range-for binders #65 and wrightkit/workshop-rs#95 — explicit bounded follow-ups; do not place them on the critical path unless real-project/end-to-end evidence proves they block the declared baseline.
• Retire frontend as an architecture boundary and consolidate the OverPy language implementation #62 — repository terminology/crate-boundary cleanup; coordinate where useful but do not let architecture cleanup outrank compiler-semantic blockers.

Scope

• Consume workshop-rs through documented public contracts and reproducible release/catalog identity.
• Resolve canonical actions, values, events, enums, settings, locale behavior, validation, and emission through workshop-rs; do not duplicate Workshop ownership in opy-rs.
• Preserve OPY-specific syntax, aliases, preprocessing, macros, semantic identities, source spans, diagnostics, and higher-level behavior in opy-rs.
• Lower supported OPY semantics directly into canonical WIR without another temporary Workshop IR.
• Expose standalone compilation only when the pipeline has real end-to-end evidence.
• Advance support claims using observable/canonical semantic equivalence, not emitted-text identity.

Acceptance criteria

• Lower the declared OPY semantic surface into canonical Workshop WIR #36, Integrate Workshop-dependent settings, locale, directive, and hook behavior #37, and Expose OPY compilation and close the end-to-end compatibility gate #38 complete with independent implementation/test evidence against a released, reproducible Workshop baseline.
• opy-rs remains independently useful for OPY parsing/check/inspect/source semantics without requiring Workshop emission.
• OPY semantic identities/signatures link to canonical Workshop identities without duplicating authoritative Workshop data.
• Supported OPY corpus cases lower to structurally and canonically valid WIR and emit through workshop-rs.
• Settings, catalog-backed builtin/member/enum validation, locale/emission behavior, evidence-backed backend directive effects, and post-compile hooks have integration tests.
• The public library/CLI compiler contract has structured, source-attributed failure behavior suitable for tooling and CI.
• End-to-end support status is grounded in representative real-project/corpus evidence; known gaps remain explicit and cannot count as success.