net: add UDP listen, resolver, DNSError, and TCP listener APIs for wasm (#63)

* net: add UDP listen, resolver, DNSError, and TCP listener APIs for wasm

TinyGo's net package was missing several symbols that upstream Go's
js/wasm net declares, blocking builds that pull pion/transport, pion/dtls,
and similar (via netbird's WASM client). Add them, backed by the existing
netdev abstraction so they compile for all targets and no-op cleanly under
nopNetdev (matching Go's js runtime behavior):

- DNSError type (dnserror.go), copied from Go 1.26.2.
- Resolver + DefaultResolver with LookupHost/LookupIP/LookupIPAddr/
  LookupNetIP/LookupPort; LookupHost/LookupIP package funcs; Dialer.Resolver
  field for API compatibility.
- UDPConn: ListenUDP, ReadFromUDP(AddrPort), WriteToUDP(AddrPort),
  SetReadBuffer, SetWriteBuffer.
- TCPConn: CloseRead, SetNoDelay, SetReadBuffer, SetWriteBuffer,
  ReadFrom(io.Reader).
- TCPListener: ListenTCP, AcceptTCP, SetDeadline; ListenPacket package func.
- Interface: Addrs, MulticastAddrs stubs.

* more complete PR for adding more net support (#64)

* format unixsock

http/response.go

@@ -14,6 +14,7 @@ package http
 import (
 	"bufio"
 	"bytes"
+	"crypto/tls"
 	"errors"
 	"fmt"
 	"io"
@@ -117,6 +118,11 @@ type Response struct {
 	// Request's Body is nil (having already been consumed).
 	// This is only populated for Client requests.
 	Request *Request
+
+	// TLS contains information about the TLS connection on which the response
+	// was received. It is nil for unencrypted responses. TINYGO: populated only
+	// if a caller sets it; the wasm fetch path leaves it nil.
+	TLS *tls.ConnectionState
 }
 
 // Cookies parses and returns the cookies set in the Set-Cookie headers.