Account Socket.IO middleware corpus and causal errors

Bun compatibility slice

Account for js/third_party/socket.io/socket.io-middleware.test.ts at exhaustive corpus position 4054.

Bun currently disables this entire middleware suite with describe.skip. Home should:

• resolve its Socket.IO support import and preserve the suite-level todo;
• classify it as neither unsupported nor allowed-empty;
• add it to the permanent third-party matrix;
• permanently verify that middleware rejection preserves its original cause, operation, phase, session id, and causal stack without exposing packet contents.

Tracked from #66.

Implemented and pushed in 7cf794763.

Home now resolves the middleware fixture's support import, preserves Bun's intentional suite-level describe.skip, and permanently asserts its explicit todo status.

The permanent diagnostic suite also now proves that a Socket.IO middleware rejection retains ERR_SOCKET_IO_PROTOCOL, the socket.io.middleware operation, middleware phase, logical session id, original TypeError cause, and causal stack while excluding the private CONNECT payload.

Verification:

• focused position 4054: 1 file, 0 failed, 1 todo, 0 unsupported/allowed-empty;
• Socket.IO positions 4050–4054: 5 files, 13 passed, 6 explicit todos, 0 failed/unsupported/allowed-empty;
• permanent gRPC error-stack, SQL adapter-contract, third-party corpus, and 36-case diagnostic suites all pass.