Add list command to show manifest contents

- mfer list: shows file paths one per line
- mfer list -l/--long: shows size, mtime, and path
- mfer list --print0: NUL-separated output for xargs -0

internal/cli/mfer.go

@@ -216,6 +216,26 @@ func (mfa *CLIApp) run(args []string) {
 					return nil
 				},
 			},
+			{
+				Name:      "list",
+				Aliases:   []string{"ls"},
+				Usage:     "List files in manifest",
+				ArgsUsage: "[manifest file]",
+				Action: func(c *cli.Context) error {
+					return mfa.listManifestOperation(c)
+				},
+				Flags: []cli.Flag{
+					&cli.BoolFlag{
+						Name:    "long",
+						Aliases: []string{"l"},
+						Usage:   "Show size and mtime",
+					},
+					&cli.BoolFlag{
+						Name:  "print0",
+						Usage: "Separate entries with NUL character (for xargs -0)",
+					},
+				},
+			},
 			{
 				Name:  "fetch",
 				Usage: "fetch manifest and referenced files",