Step 7: Remaining commands — remove, verify, list, diff.

Remove: untrack files, remove manifest entries, save. 2 tests.
Verify: check blobs against manifest hashes, report ok/mismatch/missing. 3 tests.
List: return all tracked entries, CLI formats by type. 2 tests.
Diff: compare stored blob vs current file, simple line diff. 3 tests.

Each command in its own file (garden/<cmd>.go) for parallel development.
Remove, verify, list implemented by parallel worktree agents; diff manual.

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

cmd/sgard/diff.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/kisom/sgard/garden"
+	"github.com/spf13/cobra"
+)
+
+var diffCmd = &cobra.Command{
+	Use:   "diff <path>",
+	Short: "Show differences between stored and current file",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		g, err := garden.Open(repoFlag)
+		if err != nil {
+			return err
+		}
+
+		d, err := g.Diff(args[0])
+		if err != nil {
+			return err
+		}
+
+		if d == "" {
+			fmt.Println("No changes.")
+		} else {
+			fmt.Print(d)
+		}
+
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(diffCmd)
+}