Account Socket.IO socket middleware skipped corpus

Bun compatibility slice

Account for js/third_party/socket.io/socket.io-socket-middleware.test.ts at exhaustive corpus position 4057.

The outer suite is active, but Bun individually skips both tests until its Blob/isBinary bug is fixed. Home should resolve the support import, preserve both explicit todos, avoid unsupported or allowed-empty classification, and pin the fixture in the permanent third-party matrix so upstream reactivation is visible.

Tracked from #66.

Implemented and pushed in b4a369936.

Home now resolves the socket-middleware fixture's support import, preserves both Bun-skipped cases as explicit todos, and permanently asserts todo=2 instead of unsupported or allowed-empty classification.

Verification:

• focused position 4057: 1 file, 0 failed, 2 todos, 0 unsupported/allowed-empty;
• Socket.IO positions 4050–4057: 8 files, 13 passed, 10 explicit todos, 0 failed/unsupported/allowed-empty;
• permanent gRPC error-stack, SQL adapter-contract, third-party corpus, and 36-case diagnostic suites all pass.