feat: add go-process daemon wrapper for blockchain service

NewDaemonProcess creates a managed daemon with:
- PID file (single-instance enforcement)
- Health endpoint on :47942
- Process registry entry

Replaces raw http.ListenAndServe in service.go lifecycle.
go-process handles signals, graceful shutdown, health checks.

Co-Authored-By: Charon <charon@lethean.io>

service_process.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2017-2026 Lethean (https://lt.hn)
+// SPDX-License-Identifier: EUPL-1.2
+
+package blockchain
+
+import (
+	"dappco.re/go/core"
+	"dappco.re/go/core/process"
+)
+
+// NewDaemonProcess creates a go-process managed daemon for the blockchain service.
+//
+//	d := blockchain.NewDaemonProcess(dataDir)
+//	d.Start()
+//	d.SetReady(true)
+//	d.Run(ctx)
+func NewDaemonProcess(dataDir string) *process.Daemon {
+	return process.NewDaemon(process.DaemonOptions{
+		PIDFile:    core.JoinPath(dataDir, "blockchain.pid"),
+		HealthAddr: ":47942",
+		Registry:   process.DefaultRegistry(),
+		RegistryEntry: process.DaemonEntry{
+			Code:   "dappco.re/go/core/blockchain",
+			Daemon: "chain",
+		},
+	})
+}