Step 4: Garden core with Init, Open, Add and CLI commands.

Garden package ties manifest and store together. Supports adding
files (hashed and stored as blobs), directories (manifest-only),
and symlinks (target recorded). Paths under $HOME are stored as
~/... in the manifest for portability. CLI init and add commands
wired up via cobra.

8 tests covering init, open, add for all three entry types,
duplicate rejection, HashFile, and tilde path expansion.

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

cmd/sgard/add.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kisom/sgard/garden"
+	"github.com/spf13/cobra"
+)
+
+var addCmd = &cobra.Command{
+	Use:   "add <path>...",
+	Short: "Track files, directories, or symlinks",
+	Args:  cobra.MinimumNArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		g, err := garden.Open(repoFlag)
+		if err != nil {
+			return err
+		}
+
+		if err := g.Add(args); err != nil {
+			return err
+		}
+
+		fmt.Printf("Added %d path(s)\n", len(args))
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(addCmd)
+}

cmd/sgard/init.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kisom/sgard/garden"
+	"github.com/spf13/cobra"
+)
+
+var initCmd = &cobra.Command{
+	Use:   "init",
+	Short: "Create a new sgard repository",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		_, err := garden.Init(repoFlag)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("Initialized sgard repository at %s\n", repoFlag)
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(initCmd)
+}