Add --version flag and version printing

Add support for printing the app version and exiting. Introduce ShowVersion in Config and parse --version / -v flags, add a Version variable (default "dev") in main, and print "hideTop <version>" when the flag is set. Update README to document the --version flag and show how to embed a git tag into the binary using -ldflags.

Author: youhide

README.md

@@ -32,6 +32,9 @@ Built with [Bubble Tea](https://github.com/charmbracelet/bubbletea) and [Lip Glo
 go build -o hideTop ./src/
 ./hideTop                     # default 1s refresh
 ./hideTop --interval 500ms    # faster refresh
+./hideTop --version           # print version and exit
+# local build with git tag in --version:
+go build -ldflags "-X main.Version=$(git describe --tags --always --dirty)" -o hideTop ./src/
 ```
 
 ## Project structure

internal/config/config.go

@@ -7,15 +7,19 @@ import (
 
 type Config struct {
 	RefreshInterval time.Duration
+	ShowVersion     bool
 }
 
 func Parse() Config {
 	interval := flag.Duration("interval", 1*time.Second,
 		"metrics refresh interval (e.g. 500ms, 1s, 2s)")
+	showVersion := flag.Bool("version", false, "print version and exit")
+	showVersionShort := flag.Bool("v", false, "print version and exit")
 	flag.Parse()
 
 	cfg := Config{
 		RefreshInterval: *interval,
+		ShowVersion:     *showVersion || *showVersionShort,
 	}
 
 	if cfg.RefreshInterval < 100*time.Millisecond {

src/main.go

@@ -10,8 +10,15 @@ import (
 	"github.com/youhide/hideTop/internal/config"
 )
 
+var Version = "dev"
+
 func main() {
 	cfg := config.Parse()
+	if cfg.ShowVersion {
+		fmt.Printf("hideTop %s\n", Version)
+		return
+	}
+
 	m := app.New(cfg)
 
 	p := tea.NewProgram(m,