Complete end-to-end DEL/OSTW compilation and integration compatibility gate

[Teakowa]

Parent: #8

Goal

Turn the integrated DEL language/lowering stack into an evidence-backed end-to-end compiler path that produces validated canonical Workshop semantics and emits through released workshop-rs, then close the declared Workshop-dependent compatibility surface without hiding known gaps.

Context

#29–#32 establish the released dependency/provider boundary, core HIR -> WIR lowering, advanced runtime lowering, and project/compiler surfaces. This issue is the integration gate: it should expose a stable compile path and prove compatibility through independently grounded corpus evidence rather than generated-text identity.

workshop-rs#12 is complete and shipped in workshop-rs 0.1.1. The evidence-report foundation from #26 has already begun landing; canonical Workshop feature identities/census remain owned by wrightkit/workshop-rs#10 and should be consumed when available.

Scope

• Expose a library compile API that runs project loading -> semantic analysis -> typed DEL HIR -> canonical WIR lowering -> WIR/catalog validation -> workshop-rs emission.
• Add a standalone CLI compilation surface once the library contract is stable, with target locale/emission controls delegated to workshop-rs rather than reimplemented locally.
• Preserve structured DEL diagnostics and source provenance across source-language, lowering, canonical validation, and emission failures.
• Run representative real-world DEL/OSTW projects and focused/minimized fixtures through the complete pipeline.
• Extend the evidence-driven compatibility report so Workshop-dependent cases distinguish matched behavior, known gaps, unsupported cases, unexpected regressions/divergence, and inconclusive evidence.
• Consume canonical feature identities/census contracts from workshop-rs#10 when available so failures can be attributed to Workshop capabilities without copying canonical definitions into deltin-rs.
• Compare compilation results by valid canonical Workshop semantics and semantic/normalized equivalence. Exact generated text, temporary variables, helper names, optimizer shape, or whitespace are evidence only when a declared observable contract requires them.
• Promote workshop-lowering.* support-matrix entries to end-to-end-supported only where the corresponding source and Workshop evidence passes.
• Re-run the complete Workshop-independent test suite to ensure backend integration does not regress parsing, semantic queries, diagnostics, HIR, or tooling APIs.
• Update public compatibility/limitations documentation from actual final evidence, without adding issue-status TODOs back to README.

Non-goals

• Workshop -> DEL/OSTW reconstruction (Add Workshop-to-DEL decompilation and close remaining declared compatibility gaps #9).
• Declaring 100% compatibility by counting known gaps as passes.
• Reproducing upstream compiler output identity.
• Moving canonical Workshop corpus/catalog data into deltin-rs.
• Expanding language features merely to increase a compatibility count.

Acceptance criteria

• Supported .del / .ostw projects compile through released canonical workshop-rs WIR/validation/emission with deterministic structured outcomes.
• Runtime-sensitive cases from Implement DEL object, reference, dispatch, recursion, and closure runtime lowering #31 have end-to-end compatibility evidence, not only HIR/oracle tests.
• Project/compiler surfaces from Integrate DEL project, embedded Workshop, settings, strings, and backend compiler surfaces #32 have explicit supported/unsupported states backed by evidence.
• Workshop-dependent compatibility reporting uses canonical Workshop feature identities when the workshop-rs#10 contract is available and never invents a parallel catalog.
• Known gaps and unsupported cases remain visible and cannot be reported as successful compatibility.
• All newly claimed end-to-end-supported matrix entries cite concrete evidence paths.
• Existing Workshop-independent language/tooling behavior remains regression-green.
• The remaining Integrate DEL lowering and runtime compatibility with workshop-rs #8 gaps, if any, are explicitly justified; otherwise Integrate DEL lowering and runtime compatibility with workshop-rs #8 can close and Add Workshop-to-DEL decompilation and close remaining declared compatibility gaps #9 may be re-evaluated against the resulting canonical integration.

Dependencies

• Establish the workshop-rs dependency and canonical catalog provider #29, Lower core DEL HIR into canonical workshop-rs WIR #30, Implement DEL object, reference, dispatch, recursion, and closure runtime lowering #31, Integrate DEL project, embedded Workshop, settings, strings, and backend compiler surfaces #32.
• workshop-rs#12: complete and already included in the released dependency baseline.
• Ground DEL/OSTW compatibility tests in real-project regressions and Workshop conformance evidence #26 for the DEL evidence-report architecture; its Workshop census mapping depends on wrightkit/workshop-rs#10.