Add connectionOptions support to createServer

[brozeph]

This PR adds options.connectionOptions as a narrower alternative to accepting arbitrary Duplex streams from connectionFilter.

The intent is to keep connectionFilter focused on allow/deny policy while giving callers a separate hook to customize the outbound TCP dial. simple-socks still owns the call to net.createConnection, so existing socket lifecycle behavior, timeouts, piping, and proxy events remain under the library’s control.

This supports use cases like destination rewriting, local bind customization, and routing through a local TCP adapter. For SSH forwarding or other non-net.Socket transports, callers can bridge through a local TCP listener and return those listener options from connectionOptions, rather than returning the stream directly.

Included:

• TypeScript declarations for connectionOptions
• README documentation and SSH adapter example
• tests for host/port rewriting and hook error handling
• v3.6.0 changelog entry
• dependency refresh and audit cleanup

To accomplish what #76 is trying to address:

import net from "net";
import socks5 from "simple-socks";

// `ssh` is an already-connected ssh2 Client instance.
function createSshForwardTarget(ssh, destination, origin, callback) {
  const forwarder = net.createServer((localSocket) => {
    // This listener is for one SOCKS request only.
    forwarder.close();

    ssh.forwardOut(
      origin.address,
      origin.port,
      destination.address,
      destination.port,
      (err, sshStream) => {
        if (err) {
          localSocket.destroy(err);
          return;
        }

        localSocket.pipe(sshStream);
        sshStream.pipe(localSocket);

        localSocket.once("close", () => sshStream.destroy());
        localSocket.once("error", () => sshStream.destroy());
        sshStream.once("close", () => localSocket.destroy());
        sshStream.once("error", () => localSocket.destroy());
      },
    );
  });

  forwarder.once("error", callback);

  forwarder.listen(0, "127.0.0.1", () => {
    const address = forwarder.address();

    callback(null, {
      host: address.address,
      port: address.port,
    });
  });
}

const server = socks5.createServer({
  connectionOptions(destination, origin, defaults, callback) {
    createSshForwardTarget(ssh, destination, origin, (err, target) => {
      if (err) {
        return callback(err);
      }

      return callback(null, {
        ...defaults,
        ...target,
      });
    });
  },
});

server.listen(1080, "127.0.0.1");

[codecov]

Codecov Report

❌ Patch coverage is 90.47619% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.03%. Comparing base (641b108) to head (178aeda).

Files with missing lines	Patch %	Lines
src/socks5.js	90.47%	16 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #77      +/-   ##
==========================================
+ Coverage   86.75%   87.03%   +0.27%     
==========================================
  Files           2        2              
  Lines         657      702      +45     
==========================================
+ Hits          570      611      +41     
- Misses         87       91       +4     

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