Add error status code mapping tests

[ChristianPavilonis]

Summary

• Adds deterministic unit coverage for TrustedServerError::status_code().
• Verifies every current error variant maps to the expected HTTP status code.

Changes

File	Change
crates/trusted-server-core/src/error.rs	Added a focused unit test covering status-code mappings for all TrustedServerError variants.

Closes

Closes #448

Test plan

• cargo test --workspace
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo fmt --all -- --check
• JS tests: cd crates/js/lib && npx vitest run
• JS format: cd crates/js/lib && npm run format
• Docs format: cd docs && npm run format
• WASM build: cargo build --package trusted-server-adapter-fastly --release --target wasm32-wasip1
• Manual testing via fastly compute serve
• Other: cargo test -p trusted-server-core error::tests; cargo test -p trusted-server-core

Checklist

• Changes follow CLAUDE.md conventions
• No unwrap() in production code — use expect("should ...")
• Uses tracing macros (not println!)
• New code has tests
• No secrets or credentials committed

[aram356]

Summary

Clean, well-scoped test-only change. Adds status_code_returns_expected_http_status_for_each_variant, a table-driven test that locks the TrustedServerError::status_code() → HTTP-status contract. Verified all 17 enum variants are exercised and every expected status matches the implementation exactly. Closes #448.

Verdict: APPROVE.

Non-blocking

🌱 seedling

• Exhaustiveness isn't compile-enforced — The new cases array is hand-maintained, so a future 18th variant would compile and pass without being covered here (it would simply go untested). The practical risk is low: status_code()'s match has no _ arm, so a new variant always forces an explicit mapping decision in production code — only its test coverage could be forgotten, not its handling. Flagging for awareness; no change requested. Driving the expected value through a second exhaustive match in the test would mostly duplicate the production match for little added assurance, so I'd lean against it.

👍 praise

• Complete and accurate coverage — all 17 variants present, each mapped to the correct status; complements the existing user_message() tests without overlap. Follows conventions: "should ..." assertion messages, String::from(...), fictional example.com data only.

CI Status

• cargo test: PASS (required)
• cargo fmt: PASS (required)
• format-typescript: PASS (required)
• format-docs: PASS (required)
• vitest: PASS
• Analyze (rust): PASS
• Analyze (javascript-typescript): PASS
• Analyze (actions): PASS
• CodeQL: PASS
• integration tests: PASS
• browser integration tests: PASS
• prepare integration artifacts: PASS

Test passes locally in an isolated worktree at head c65c2a0 (cargo test -p trusted-server-core error::tests → 3 passed).

[aram356]

Follow-up to my approval: one optional inline suggestion to make the variant coverage compile-enforced. The PR is already approved — this is a non-blocking ♻️ refactor you can one-click apply or skip.