fix pre delete dirmd set dir bug and implement last git sha and commit#

internal/git/git.go

@@ -0,0 +1,37 @@
+package git
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+type CommitInfo struct {
+	ShortSHA string
+	Message  string
+}
+
+func GetCommitInfo(rootDir string) *CommitInfo {
+	cmd := exec.Command("git", "-C", rootDir, "log", "-1", "--format=%h %s")
+	output, err := cmd.Output()
+	if err != nil {
+		return nil
+	}
+
+	parts := strings.SplitN(strings.TrimSpace(string(output)), " ", 2)
+	if len(parts) < 2 {
+		return nil
+	}
+
+	return &CommitInfo{
+		ShortSHA: parts[0],
+		Message:  parts[1],
+	}
+}
+
+func FormatCommitLine(info *CommitInfo) string {
+	if info == nil {
+		return ""
+	}
+	return fmt.Sprintf("> Commit: %s (%s)\n", info.ShortSHA, info.Message)
+}