WIP: Save agent roles integration work before CHORUS rebrand

- Agent roles and coordination features
- Chat API integration testing
- New configuration and workspace management

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

vendor/github.com/multiformats/go-multistream/client.go

@@ -0,0 +1,151 @@
+package multistream
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"runtime/debug"
+)
+
+// ErrNotSupported is the error returned when the muxer doesn't support
+// the protocols tried for the handshake.
+type ErrNotSupported[T StringLike] struct {
+
+	// Slice of protocols that were not supported by the muxer
+	Protos []T
+}
+
+func (e ErrNotSupported[T]) Error() string {
+	return fmt.Sprintf("protocols not supported: %v", e.Protos)
+}
+
+func (e ErrNotSupported[T]) Is(target error) bool {
+	_, ok := target.(ErrNotSupported[T])
+	return ok
+}
+
+// ErrNoProtocols is the error returned when the no protocols have been
+// specified.
+var ErrNoProtocols = errors.New("no protocols specified")
+
+// SelectProtoOrFail performs the initial multistream handshake
+// to inform the muxer of the protocol that will be used to communicate
+// on this ReadWriteCloser. It returns an error if, for example,
+// the muxer does not know how to handle this protocol.
+func SelectProtoOrFail[T StringLike](proto T, rwc io.ReadWriteCloser) (err error) {
+	defer func() {
+		if rerr := recover(); rerr != nil {
+			fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+			err = fmt.Errorf("panic selecting protocol: %s", rerr)
+		}
+	}()
+
+	errCh := make(chan error, 1)
+	go func() {
+		var buf bytes.Buffer
+		if err := delitmWriteAll(&buf, []byte(ProtocolID), []byte(proto)); err != nil {
+			errCh <- err
+			return
+		}
+		_, err := io.Copy(rwc, &buf)
+		errCh <- err
+	}()
+	// We have to read *both* errors.
+	err1 := readMultistreamHeader(rwc)
+	err2 := readProto(proto, rwc)
+	if werr := <-errCh; werr != nil {
+		return werr
+	}
+	if err1 != nil {
+		return err1
+	}
+	if err2 != nil {
+		return err2
+	}
+	return nil
+}
+
+// SelectOneOf will perform handshakes with the protocols on the given slice
+// until it finds one which is supported by the muxer.
+func SelectOneOf[T StringLike](protos []T, rwc io.ReadWriteCloser) (proto T, err error) {
+	defer func() {
+		if rerr := recover(); rerr != nil {
+			fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
+			err = fmt.Errorf("panic selecting one of protocols: %s", rerr)
+		}
+	}()
+
+	if len(protos) == 0 {
+		return "", ErrNoProtocols
+	}
+
+	// Use SelectProtoOrFail to pipeline the /multistream/1.0.0 handshake
+	// with an attempt to negotiate the first protocol. If that fails, we
+	// can continue negotiating the rest of the protocols normally.
+	//
+	// This saves us a round trip.
+	switch err := SelectProtoOrFail(protos[0], rwc); err.(type) {
+	case nil:
+		return protos[0], nil
+	case ErrNotSupported[T]: // try others
+	default:
+		return "", err
+	}
+	proto, err = selectProtosOrFail(protos[1:], rwc)
+	if _, ok := err.(ErrNotSupported[T]); ok {
+		return "", ErrNotSupported[T]{protos}
+	}
+	return proto, err
+}
+
+func selectProtosOrFail[T StringLike](protos []T, rwc io.ReadWriteCloser) (T, error) {
+	for _, p := range protos {
+		err := trySelect(p, rwc)
+		switch err := err.(type) {
+		case nil:
+			return p, nil
+		case ErrNotSupported[T]:
+		default:
+			return "", err
+		}
+	}
+	return "", ErrNotSupported[T]{protos}
+}
+
+func readMultistreamHeader(r io.Reader) error {
+	tok, err := ReadNextToken[string](r)
+	if err != nil {
+		return err
+	}
+
+	if tok != ProtocolID {
+		return errors.New("received mismatch in protocol id")
+	}
+	return nil
+}
+
+func trySelect[T StringLike](proto T, rwc io.ReadWriteCloser) error {
+	err := delimWriteBuffered(rwc, []byte(proto))
+	if err != nil {
+		return err
+	}
+	return readProto(proto, rwc)
+}
+
+func readProto[T StringLike](proto T, r io.Reader) error {
+	tok, err := ReadNextToken[T](r)
+	if err != nil {
+		return err
+	}
+
+	switch tok {
+	case proto:
+		return nil
+	case "na":
+		return ErrNotSupported[T]{[]T{proto}}
+	default:
+		return fmt.Errorf("unrecognized response: %s", tok)
+	}
+}