Integrate DEL lowering and runtime compatibility with workshop-rs

[Teakowa]

Parent: #1

Goal

Connect the completed DEL/OSTW semantic implementation and typed HIR to the canonical workshop-rs model and complete the Workshop-dependent compiler/runtime compatibility surface.

Current integration baseline

The former dependency blocker is resolved:

• Reach Workshop-independent DEL/OSTW frontend completeness and expose tooling APIs #7 Workshop-independent language readiness is complete.
• wrightkit/workshop-rs#2 canonical core is complete.
• wrightkit/workshop-rs#12 canonical rule-event surface is complete.
• Wright cutover #143 is complete and Wright v0.2.4 is released using workshop-rs as the single canonical Workshop implementation.
• workshop-rs 0.1.1 is published on crates.io and includes the reviewed event contract. deltin-rs should consume this released crate rather than a Git SHA.

Integration identity is now release-based: declared crate version + exact Cargo.lock resolution + workshop-rs CatalogIdentity. A manually synchronized repository revision constant is not part of the public contract.

Execution issues

• Establish the workshop-rs dependency and canonical catalog provider #29 — Establish the released workshop-rs dependency and canonical catalog provider.
• Lower core DEL HIR into canonical workshop-rs WIR #30 — Lower core DEL HIR into canonical workshop-rs WIR.
• Implement DEL object, reference, dispatch, recursion, and closure runtime lowering #31 — Implement DEL object, reference, dispatch, recursion, and closure runtime lowering.
• Integrate DEL project, embedded Workshop, settings, strings, and backend compiler surfaces #32 — Integrate DEL project, embedded Workshop, settings, strings, and backend compiler surfaces.
• Complete end-to-end DEL/OSTW compilation and integration compatibility gate #33 — Complete end-to-end DEL/OSTW compilation and the integration compatibility gate.

Cross-repository / evidence work:

• wrightkit/workshop-rs#10 — canonical Workshop conformance feature identities/census.
• Ground DEL/OSTW compatibility tests in real-project regressions and Workshop conformance evidence #26 — DEL/OSTW evidence-driven compatibility reporting and real-project regression model; its evidence-report foundation can proceed in parallel, while canonical census mapping consumes workshop-rs#10 when available.

Scope

• Consume authoritative Workshop actions, values, events, enums, settings, content identifiers, WIR, validation, localization, and emission through documented workshop-rs public contracts.
• Resolve Workshop-facing names through a deltin-rs-owned WorkshopProvider adapter backed by the canonical catalog; dependency direction remains deltin-rs -> workshop-rs.
• Lower typed DEL HIR into canonical WIR while preserving source provenance and keeping concrete target encodings out of source-language/HIR contracts.
• Implement Workshop-dependent lowering for rules, expressions, storage intent, classes/objects, allocation/deletion, virtual dispatch, references/generation validation, recursion, lambdas, strings, embedded Workshop, settings, and other inventory-backed runtime/compiler semantics.
• Implement variable/storage allocation and target-specific helper structures only where required by observable DEL/OSTW semantics, Workshop validity/limits, or evidence-backed stability/cost contracts.
• Run focused, minimized, and real-project end-to-end compatibility tests using semantic/normalized Workshop equivalence rather than generated-text identity.
• Advance workshop-lowering.* support-matrix entries to end-to-end-supported only with concrete source and canonical Workshop evidence.

Non-goals

• Reintroducing canonical Workshop semantics, catalog data, locale tables, WIR, parser, validation, or emitter implementation into deltin-rs.
• Coupling workshop-rs back to DEL-specific syntax or semantics.
• Matching upstream temporary variables, helper-rule names, formatting, storage layouts, optimizer internals, or emitted text where observable semantics do not require them.
• Treating output-format preferences as correctness requirements unless a declared source/round-trip contract requires otherwise.
• Workshop -> DEL decompilation; tracked separately in Add Workshop-to-DEL decompilation and close remaining declared compatibility gaps #9 after forward integration is stable.

Acceptance criteria

• deltin-rs consumes Workshop semantics only through reviewed released workshop-rs public contracts, with reproducibility provided by the crate version, lockfile resolution, and catalog identity.
• Supported DEL/OSTW corpus and representative real-world projects lower to valid canonical WIR and emit through workshop-rs.
• Runtime-sensitive features such as allocation/deletion, inheritance/dispatch, stale-reference validation, recursion, closures, and storage semantics have end-to-end evidence.
• Project/compiler surfaces such as embedded Workshop, settings, strings, comments, and chase/modify behavior have explicit evidence-backed supported/unsupported states.
• Workshop-dependent support-matrix entries advance to end-to-end-supported only with tests; known gaps remain explicit and are never counted as passes.
• Missing canonical Workshop capabilities are fixed in the owning workshop-rs repository rather than duplicated or approximated locally.
• Existing Workshop-independent parse/check/inspect/HIR/tooling behavior stays regression-green.
• No authoritative Workshop implementation is duplicated in deltin-rs.

Dependencies

The original readiness and event-contract dependencies are satisfied. The remaining cross-repository dependency for the final compatibility gate is capability evidence from workshop-rs#10; it does not block core/runtime lowering.

Planning notes

Land #29, then complete #30 against released workshop-rs 0.1.1. After the core lowering boundary is stable, #31 and #32 can proceed in parallel where their dependencies do not overlap. Keep #26 evidence work parallel. Use #33 as the integration/release gate, then reassess #9 from the actual forward contract rather than designing the decompiler early.