Mark droplet commands as deprecated in help output

Add deprecatedCommandHelpFunc to display deprecated commands in a
separate section at the bottom of the help output. The droplet commands
are now listed under "Deprecated commands" instead of in the main
command list.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: swalkinshaw

help.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/hashicorp/cli"
+)
+
+func deprecatedCommandHelpFunc(commandNames []string, f cli.HelpFunc) cli.HelpFunc {
+	return func(commands map[string]cli.CommandFactory) string {
+		var buf bytes.Buffer
+		if len(commandNames) > 0 {
+			buf.WriteString("\n\nDeprecated commands:\n")
+		}
+
+		maxKeyLen := 0
+		keys := make([]string, 0, len(commandNames))
+		filteredCommands := make(map[string]cli.CommandFactory)
+
+		for key, command := range commands {
+			for _, deprecatedKey := range commandNames {
+				if key != deprecatedKey {
+					filteredCommands[key] = command
+				}
+			}
+		}
+
+		for _, key := range commandNames {
+			if len(key) > maxKeyLen {
+				maxKeyLen = len(key)
+			}
+
+			keys = append(keys, key)
+		}
+
+		sort.Strings(keys)
+
+		for _, key := range keys {
+			commandFunc, _ := commands[key]
+			command, _ := commandFunc()
+			key = fmt.Sprintf("%s%s", key, strings.Repeat(" ", maxKeyLen-len(key)))
+			buf.WriteString(fmt.Sprintf("    %s    %s\n", key, command.Synopsis()))
+		}
+
+		return f(filteredCommands) + buf.String()
+	}
+}

main.go

@@ -19,6 +19,9 @@ import (
 // To be replaced by goreleaser build flags.
 var version = "canary"
 var updaterRepo = ""
+var deprecatedCommands = []string{
+	"droplet",
+}
 
 func main() {
 	c := cli.NewCLI("trellis", version)
@@ -215,7 +218,7 @@ func main() {
 	}
 
 	c.HiddenCommands = []string{"venv", "venv hook"}
-	c.HelpFunc = cli.BasicHelpFunc("trellis")
+	c.HelpFunc = deprecatedCommandHelpFunc(deprecatedCommands, cli.BasicHelpFunc("trellis"))
 
 	if trellis.CliConfig.LoadPlugins {
 		pluginPaths := filepath.SplitList(os.Getenv("PATH"))