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_stub.go

@@ -0,0 +1,13 @@
+//go:build !p2p
+
+package client
+
+// MeshNode is a no-op stub unless built with `-tags p2p`.
+type MeshNode struct{}
+
+func NewMeshNode(_ *AgentClient) *MeshNode { return &MeshNode{} }
+
+func (m *MeshNode) Start() error { return nil }
+
+func (m *MeshNode) BroadcastToMesh(_ Message) {}
+