chore(recoverydiag): 补齐 go.mod 与 main.go（与其他插件结构一致）

example/recoverydiag/go.mod

@@ -0,0 +1,7 @@
+module recoverydiag
+
+go 1.25.0
+
+require gitcode.com/JianFeeeee/homeagent-sdk v0.0.0
+
+replace gitcode.com/JianFeeeee/homeagent-sdk => ../../

example/recoverydiag/main.go

@@ -0,0 +1,11 @@
+//go:build !windows || !cgo
+
+package main
+
+import (
+	sdk "gitcode.com/JianFeeeee/homeagent-sdk/sdk"
+)
+
+func NewPlugin(name string, config map[string]interface{}) (sdk.Plugin, error) {
+	return NewPluginFactory(name, config)
+}