Step 5: Checkpoint and Status.

Checkpoint re-hashes all tracked files, stores changed blobs, and
updates per-file timestamps only when content changes. Missing files
are skipped gracefully. Status compares each tracked entry against
the filesystem and reports ok/modified/missing.

CLI: sgard checkpoint [-m message], sgard status.
4 new tests (changed file, unchanged file, missing file, status).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cmd/sgard/checkpoint.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kisom/sgard/garden"
+	"github.com/spf13/cobra"
+)
+
+var checkpointMessage string
+
+var checkpointCmd = &cobra.Command{
+	Use:   "checkpoint",
+	Short: "Re-hash all tracked files and update the manifest",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		g, err := garden.Open(repoFlag)
+		if err != nil {
+			return err
+		}
+
+		if err := g.Checkpoint(checkpointMessage); err != nil {
+			return err
+		}
+
+		fmt.Println("Checkpoint complete.")
+		return nil
+	},
+}
+
+func init() {
+	checkpointCmd.Flags().StringVarP(&checkpointMessage, "message", "m", "", "checkpoint message")
+	rootCmd.AddCommand(checkpointCmd)
+}

cmd/sgard/status.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kisom/sgard/garden"
+	"github.com/spf13/cobra"
+)
+
+var statusCmd = &cobra.Command{
+	Use:   "status",
+	Short: "Show status of tracked files: ok, modified, or missing",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		g, err := garden.Open(repoFlag)
+		if err != nil {
+			return err
+		}
+
+		statuses, err := g.Status()
+		if err != nil {
+			return err
+		}
+
+		for _, s := range statuses {
+			fmt.Printf("%-10s %s\n", s.State, s.Path)
+		}
+
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(statusCmd)
+}