fix(parser): disambiguate canonical enum members

[e54-bot]

Summary

• Make parser::parse use the canonical catalog signature context by default.
• Resolve pinned Visible To and None members to stable canonical WIR identities.
• Keep unpinned enum ambiguity as an explicit structured Unsupported diagnostic.
• Document the released parse contract and add pinned oracle regression coverage.

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace --all-targets (270 tests, 24 suites)
• cargo run --locked -p workshop-rs --bin workshop-catalog-gen -- check
• git diff --check

Fixes #124

[Teakowa]

crates/workshop-rs/tests/parser.rs: released_parse_contract_resolves_pinned_oracle_members only exercises en-US. #124 explicitly requires the selected canonical identity to be proven locale-independent; the existing zh-CN parser tests cover unrelated domains, so this contract is not protected for the affected ambiguity. Add a direct non-primary-locale regression through the released parser::parse path that resolves the affected member to the same canonical WIR identity.