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/libp2p/go-libp2p-pubsub/validation_builtin.go

@@ -0,0 +1,101 @@
+package pubsub
+
+import (
+	"context"
+	"encoding/binary"
+	"sync"
+
+	"github.com/libp2p/go-libp2p/core/peer"
+)
+
+// PeerMetadataStore is an interface for storing and retrieving per peer metadata
+type PeerMetadataStore interface {
+	// Get retrieves the metadata associated with a peer;
+	// It should return nil if there is no metadata associated with the peer and not an error.
+	Get(context.Context, peer.ID) ([]byte, error)
+	// Put sets the metadata associated with a peer.
+	Put(context.Context, peer.ID, []byte) error
+}
+
+// BasicSeqnoValidator is a basic validator, usable as a default validator, that ignores replayed
+// messages outside the seen cache window. The validator uses the message seqno as a peer-specific
+// nonce to decide whether the message should be propagated, comparing to the maximal nonce store
+// in the peer metadata store. This is useful to ensure that there can be no infinitely propagating
+// messages in the network regardless of the seen cache span and network diameter.
+// It requires that pubsub is instantiated with a strict message signing policy and that seqnos
+// are not disabled, ie it doesn't support anonymous mode.
+//
+// Warning: See https://github.com/libp2p/rust-libp2p/issues/3453
+// TL;DR: rust is currently violating the spec by issuing a random seqno, which creates an
+// interoperability hazard. We expect this issue to be addressed in the not so distant future,
+// but keep this in mind if you are in a mixed environment with (older) rust nodes.
+type BasicSeqnoValidator struct {
+	mx   sync.RWMutex
+	meta PeerMetadataStore
+}
+
+// NewBasicSeqnoValidator constructs a BasicSeqnoValidator using the givven PeerMetadataStore.
+func NewBasicSeqnoValidator(meta PeerMetadataStore) ValidatorEx {
+	val := &BasicSeqnoValidator{
+		meta: meta,
+	}
+	return val.validate
+}
+
+func (v *BasicSeqnoValidator) validate(ctx context.Context, _ peer.ID, m *Message) ValidationResult {
+	p := m.GetFrom()
+
+	v.mx.RLock()
+	nonceBytes, err := v.meta.Get(ctx, p)
+	v.mx.RUnlock()
+
+	if err != nil {
+		log.Warn("error retrieving peer nonce: %s", err)
+		return ValidationIgnore
+	}
+
+	var nonce uint64
+	if len(nonceBytes) > 0 {
+		nonce = binary.BigEndian.Uint64(nonceBytes)
+	}
+
+	var seqno uint64
+	seqnoBytes := m.GetSeqno()
+	if len(seqnoBytes) > 0 {
+		seqno = binary.BigEndian.Uint64(seqnoBytes)
+	}
+
+	// compare against the largest seen nonce
+	if seqno <= nonce {
+		return ValidationIgnore
+	}
+
+	// get the nonce and compare again with an exclusive lock before commiting (cf concurrent validation)
+	v.mx.Lock()
+	defer v.mx.Unlock()
+
+	nonceBytes, err = v.meta.Get(ctx, p)
+	if err != nil {
+		log.Warn("error retrieving peer nonce: %s", err)
+		return ValidationIgnore
+	}
+
+	if len(nonceBytes) > 0 {
+		nonce = binary.BigEndian.Uint64(nonceBytes)
+	}
+
+	if seqno <= nonce {
+		return ValidationIgnore
+	}
+
+	// update the nonce
+	nonceBytes = make([]byte, 8)
+	binary.BigEndian.PutUint64(nonceBytes, seqno)
+
+	err = v.meta.Put(ctx, p, nonceBytes)
+	if err != nil {
+		log.Warn("error storing peer nonce: %s", err)
+	}
+
+	return ValidationAccept
+}