Enhances version info retrieval

Improves the `version` command to automatically extract build details (version, commit, date) from Go's `debug.ReadBuildInfo` when `ldflags` are not provided.

This allows users installing via `go install` to receive accurate version information without requiring a Makefile or explicit build flags. Updates the README to reflect this new capability.

README.md

@@ -152,6 +152,8 @@ The Makefile automatically injects version information from git tags:
 - `Commit`: Short commit hash
 - `Date`: Build timestamp
 
+**Note:** Version information is automatically included when installing via `go install` (no Makefile needed). The tool reads version info from Go's build metadata.
+
 Check the version after installing:
 ```bash
 gitlocal version

cmd/version.go

@@ -2,12 +2,14 @@ package cmd
 
 import (
 	"fmt"
+	"runtime/debug"
 
 	"github.com/spf13/cobra"
 )
 
 var (
-	// Version is set via -ldflags during build
+	// Version is set via -ldflags during build (for make install)
+	// Falls back to module version from go install
 	Version = "dev"
 	// Commit is set via -ldflags during build
 	Commit = "unknown"
@@ -20,9 +22,34 @@ var versionCmd = &cobra.Command{
 	Short: "Print version information",
 	Long:  `Display the version, commit hash, and build date of gitlocal.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Printf("gitlocal version %s\n", Version)
-		fmt.Printf("  Commit: %s\n", Commit)
-		fmt.Printf("  Built:  %s\n", Date)
+		version := Version
+		commit := Commit
+		date := Date
+
+		// If installed via 'go install', read version from build info
+		if version == "dev" {
+			if info, ok := debug.ReadBuildInfo(); ok {
+				version = info.Main.Version
+
+				// Extract commit and date from build settings
+				for _, setting := range info.Settings {
+					switch setting.Key {
+					case "vcs.revision":
+						if len(setting.Value) > 7 {
+							commit = setting.Value[:7]
+						} else {
+							commit = setting.Value
+						}
+					case "vcs.time":
+						date = setting.Value
+					}
+				}
+			}
+		}
+
+		fmt.Printf("gitlocal version %s\n", version)
+		fmt.Printf("  Commit: %s\n", commit)
+		fmt.Printf("  Built:  %s\n", date)
 	},
 }