feat: add GitHub Actions release workflow and improve docs

- Add GitHub Actions workflow for multi-platform releases
  - Build for linux/darwin on amd64/arm64
  - Auto-create GitHub Release with checksums
  - Version injection via ldflags
- Add init.d script support for install command
- Rewrite README with clearer documentation
  - Quick start guide
  - Two-node HA setup example
  - Health check configuration
  - Troubleshooting section
- Bump version to 1.2.1

🤖 Generated with [Qoder][https://qoder.com]

internal/cmd/root.go

@@ -6,12 +6,14 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// Version can be set at build time via ldflags
+var Version = "1.2.1"
+
 var rootCmd = &cobra.Command{
 	Use:   "go-alived",
 	Short: "Go-Alived - VRRP High Availability Service",
 	Long: `go-alived is a lightweight, dependency-free VRRP implementation in Go.
 It provides high availability for IP addresses with health checking support.`,
-	Version: "1.2.0",
 }
 
 func Execute() {
@@ -21,5 +23,6 @@ func Execute() {
 }
 
 func init() {
+	rootCmd.Version = Version
 	rootCmd.CompletionOptions.DisableDefaultCmd = true
 }