fix: #770 — wire net.connect(options, cb) and emit Error objects

[TheHypnoo]

Summary

Closes #770 (split off from #767 case 4).

net.connect({ host, port }, cb) — the standard Node.js options-object overload — failed with "file name contained an unexpected NUL byte" because the codegen dispatch entry only accepted the positional net.connect(port, host) form. With args: &[NA_F64, NA_STR] the second arg (the callback closure) was coerced through js_get_string_pointer_unified, the runtime read garbage bytes from the closure's memory as the hostname, and getaddrinfo's internal CString::new() blew up.

Separately, the 'error' event emitted raw NaN-boxed strings instead of Error-shaped objects, so socket.on('error', err => err.message) came back as undefined.

What changed

• Codegen dispatch (crates/perry-codegen/src/lower_call.rs): change net.connect / net.createConnection NativeModSig from &[NA_F64, NA_STR] to &[NA_F64, NA_F64] so the runtime sees both args' raw NaN-boxed bits and can discriminate the overload by tag at runtime.
• perry-ext-net (crates/perry-ext-net/src/lib.rs) and perry-stdlib (crates/perry-stdlib/src/net/mod.rs, for the PERRY_DISABLE_WELL_KNOWN=1 path):
  • js_net_socket_connect(arg1_f64, arg2_f64) now detects whether arg1 is a NaN-boxed object pointer (options form) or a regular f64 number (positional form). Plain ports like 80.0 never carry the 0x7FF8..=0x7FFF quiet-NaN prefix, so the tag check is clean.
  • For the options form, extract host / hostname / port from the object via the runtime's js_object_get_field_by_name_f64 helper.
  • Auto-register the optional connectListener (second arg in the options form) as a 'connect' listener on the new handle, matching Node spec.
  • 'error' events now ship an Error-shaped object { message: msg } so err.message works. Falls back to a bare string on alloc failure.

Test

New fixture test-files/test_net_connect_options.ts exercises the options form against an in-process node:http server (auto-registered connectListener fires) and asserts the closed-port error fires with an { message: string } object.

server listening
sock1: connectListener fired
sock2 error typeof: object
sock2 error message typeof: string
sock2 error has message: yes
done

cargo test --release -p perry-ext-net -p perry-stdlib --lib — all green. Regression-checked fetch / axios (still work) and positional net.connect(port, host) + socket.on('connect', cb) (still works).

Known limitations

The positional net.connect(port, host, cb) form continues to work, though the trailing connectListener arg is not auto-registered — the dispatch entry only carries two arg slots. Users should call socket.on('connect', cb) or migrate to the options form. Extending the dispatch table to accept three positional args is a follow-up.

Test plan

• test-files/test_net_connect_options.ts runs locally on macOS arm64
• User repro from net.connect(options, cb) options-object overload corrupts host string (NUL byte) #770 (net.connect({host: 'X', port: N}, cb)) connects successfully
• 'error' listener receives object with usable .message on closed port
• fetch / axios continue to return 200
• Positional net.connect(port, host) keeps working
• cargo test --release -p perry-ext-net -p perry-stdlib --lib passes
• CI parity / cargo-test / compile-smoke green