Stabilize Fusion builds and simplify optional modules.

Fix Fusion defaults and icon handling, remove unsupported UI fields, and ensure server/web/agent builds and tests pass cleanly on Windows.

agent/client/mesh_p2p.go

@@ -0,0 +1,90 @@
+//go:build p2p
+
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+
+	"github.com/libp2p/go-libp2p"
+	"github.com/libp2p/go-libp2p/core/host"
+	"github.com/libp2p/go-libp2p/core/network"
+	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/libp2p/go-libp2p/p2p/discovery/mdns"
+)
+
+const MeshProtocol = "/aetherforge/mesh/1.0.0"
+const DiscoveryTag = "aetherforge-mesh-discovery"
+
+// MeshNode represents a libp2p peer on the local network.
+type MeshNode struct {
+	host   host.Host
+	client *AgentClient
+}
+
+// NewMeshNode creates a new P2P fallback node.
+func NewMeshNode(c *AgentClient) *MeshNode {
+	return &MeshNode{client: c}
+}
+
+// Start initializes the libp2p host and mDNS discovery.
+func (m *MeshNode) Start() error {
+	// Bind to any available local port automatically
+	h, err := libp2p.New(libp2p.ListenAddrStrings("/ip4/0.0.0.0/tcp/0"))
+	if err != nil {
+		return err
+	}
+	m.host = h
+
+	// Register the protocol handler for incoming mesh streams
+	m.host.SetStreamHandler(MeshProtocol, m.handleStream)
+
+	// Start mDNS discovery to find other agents on the LAN
+	ser := mdns.NewMdnsService(m.host, DiscoveryTag, m)
+	if err := ser.Start(); err != nil {
+		return err
+	}
+
+	log.Printf("[Mesh] P2P Node started. PeerID: %s", m.host.ID().String())
+	return nil
+}
+
+// HandlePeerFound is a callback for mDNS discovery.
+func (m *MeshNode) HandlePeerFound(pi peer.AddrInfo) {
+	if pi.ID == m.host.ID() {
+		return
+	}
+	log.Printf("[Mesh] Discovered peer on LAN: %s", pi.ID.String())
+	if err := m.host.Connect(context.Background(), pi); err != nil {
+		log.Printf("[Mesh] Failed to connect to peer %s: %v", pi.ID, err)
+	}
+}
+
+// handleStream processes incoming messages from orphaned peers.
+func (m *MeshNode) handleStream(s network.Stream) {
+	defer s.Close()
+	var msg Message
+	if err := json.NewDecoder(s).Decode(&msg); err != nil {
+		return
+	}
+
+	// If this node is actively connected to the Hub, act as a Relay.
+	// We take the incoming share payload from the orphaned peer and pass it to our active connection!
+	if m.client.conn != nil {
+		log.Printf("[Mesh] Relaying %s message from orphaned peer to Hub", msg.Type)
+		_ = m.client.write(msg)
+	}
+}
+
+// BroadcastToMesh sends a message to all connected P2P peers.
+func (m *MeshNode) BroadcastToMesh(msg Message) {
+	for _, p := range m.host.Network().Peers() {
+		s, err := m.host.NewStream(context.Background(), p, MeshProtocol)
+		if err != nil {
+			continue
+		}
+		_ = json.NewEncoder(s).Encode(msg)
+		s.Close()
+	}
+}