feat: add provenance-linked real-project evidence

[Teakowa]

Summary

Implements #20 as an independent Draft PR on the #18 contract, parallel to #19.

• Adds the provenance-linked overpy-cake complete project case and a minimized loop regression fixture.
• Adds workshop-rs-cli corpus <manifest> [--json] with structured Define the Workshop conformance result contract and stable feature identities #18 results and explicit known-gap handling.
• Gives each migrated Workshop fixture its own pinned wrightkit/workshop-rs repository/revision/path/SHA-256 tuple.
• Keeps a separate pinned wrightkit/wright OverPy 9.7.10 oracle JSON provenance with reviewed non-null SHA-256; the runner validates local fixture drift and never recomputes historical expectations from current parser/WIR output.
• Documents admission/provenance rules in ADR-0004 and the fixture README.

Evidence boundary

The complete project remains a KnownGap because the preserved bare Up spelling is ambiguous without original source context. The minimized regression is a separately attributable Matched preserved regression. No live-client behavior is claimed.

Checks

• cargo test --locked --workspace --all-targets
• cargo clippy --locked --workspace --all-targets -- -D warnings
• cargo run --locked -p workshop-rs --bin workshop-catalog-gen -- check
• cargo run --locked -p workshop-rs-cli -- corpus crates/workshop-rs/tests/fixtures/corpus/real-projects.json
• cargo fmt --all --check
• git diff --check

This PR remains stacked on PR #26 and does not introduce OPY or DEL semantics. Fixes #20.

[Teakowa]

Fresh independent QA — BLOCKED / FAIL

Exact head reviewed: 86d87535d4344e2bcafd42178356198a17661b28.

Passed checks:

• Per-fixture workshop-rs repository/revision/path/SHA-256 tuples are present and local fixture digests match.
• Wright/OverPy oracle revision/path/SHA-256/license provenance is separate and pinned.
• Full project remains KnownGap; minimized case remains Matched; known-gap and missing-manifest/error paths are visible.
• Local fmt, Clippy, workspace/all-targets tests, catalog check, corpus CLI, and diff check passed.
• Stable and Rust 1.85 CI passed; worktree is clean.

Blocking finding:

crates/workshop-rs-cli/src/corpus.rs records the pinned oracle as expectation metadata but does not read or semantically compare its content with the observed canonical WIR. An ExpectedStatus::Success case can therefore report Matched whenever the current parser/WIR validates, even if the implementation diverges from the independent oracle. This violates the independent-oracle requirement and lacks an executable divergence guard.

This is a fresh QA result; no implementation fix was applied. PR #28 is not ready for merge until the corpus comparison contract is repaired or explicitly narrowed with regression coverage.