feat(cli): mred version update subcommand

`mred version update ID [--status open|closed] [--due YYYY-MM-DD]
[--name NAME]` flips milestone status, dates, and names; at least one
flag is required (usage error otherwise) and only provided flags are
sent. Text mode prints "updated version #N", -o json re-fetches and
emits the stored version, exit codes follow the 0/1/2 convention.

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

internal/cli/commands.go

@@ -356,7 +356,7 @@ func readDesc(path string) (string, error) {
 
 func cmdVersion(args []string, stdout, stderr io.Writer) int {
 	if len(args) == 0 {
-		return usageErr(stderr, "version: expected list|create (see mred help)")
+		return usageErr(stderr, "version: expected list|create|update (see mred help)")
 	}
 	sub, rest := args[0], args[1:]
 	switch sub {
@@ -364,6 +364,8 @@ func cmdVersion(args []string, stdout, stderr io.Writer) int {
 		return cmdVersionList(rest, stdout, stderr)
 	case "create":
 		return cmdVersionCreate(rest, stdout, stderr)
+	case "update":
+		return cmdVersionUpdate(rest, stdout, stderr)
 	default:
 		return usageErr(stderr, "version: unknown subcommand %q", sub)
 	}
@@ -432,6 +434,48 @@ func dueSuffix(due string) string {
 	return "due " + due
 }
 
+func cmdVersionUpdate(args []string, stdout, stderr io.Writer) int {
+	fs, cfgPath, out := newFlags("version update", stderr)
+	status := fs.String("status", "", "open|closed")
+	due := fs.String("due", "", "due date YYYY-MM-DD")
+	name := fs.String("name", "", "new version name")
+	pos, perr := parseArgs(fs, args)
+	if perr != nil || len(pos) != 1 {
+		return usageErr(stderr, "version update: usage: mred version update ID [--status open|closed] [--due DATE] [--name NAME]")
+	}
+	id, err := strconv.Atoi(pos[0])
+	if err != nil {
+		return usageErr(stderr, "version update: ID must be numeric, got %q", pos[0])
+	}
+	if *status == "" && *due == "" && *name == "" {
+		return usageErr(stderr, "version update: nothing to update: pass at least one of --status, --due, --name")
+	}
+	if *status != "" && *status != "open" && *status != "closed" {
+		return usageErr(stderr, "version update: --status must be open|closed")
+	}
+	c, err := client(*cfgPath)
+	if err != nil {
+		return usageErr(stderr, "%v", err)
+	}
+	// The server answers 204 with an empty body; UpdateVersion never
+	// parses it. -o json re-fetches the version afterwards.
+	if err := c.UpdateVersion(context.Background(), id, redmine.VersionParams{
+		Name: *name, DueDate: *due, Status: *status,
+	}); err != nil {
+		return apiErr(stderr, err)
+	}
+	if *out == "json" {
+		v, err := c.GetVersion(context.Background(), id)
+		if err != nil {
+			return apiErr(stderr, err)
+		}
+		emitJSON(stdout, map[string]any{"version": v})
+		return 0
+	}
+	fmt.Fprintf(stdout, "updated version #%d\n", id)
+	return 0
+}
+
 // --- category -----------------------------------------------------------------
 
 func cmdCategory(args []string, stdout, stderr io.Writer) int {