TinyGo doesnt have networking in WASI[0] and the WASM websocket module[1] was last updated 5 years ago. Go without stdlib is not Go.
For embedded systems, see https://github.com/tinygo-org/net
For WASI, check out WASI Preview 2, https://docs.wasmtime.dev/api/wasmtime_wasi/p2/index.html
Interestingly enough for the C and C++ folks, compiler specific dialects for embedded without standard library, are still argued for as if being C and C++.