fix: error on unknown flags, standardize help format, move skills dispatch

Fixes #581: agent and gateway commands now error on unknown flags instead
of silently ignoring them.

Fixes #582: auth, cron, and skills help text now includes Usage header
and --help in flags list, matching doctor command format.

Fixes #585: skills subcommand dispatch moved from main.go to cmd_skills.go
via new skillsCmd() function.

cmd/picoclaw/cmd_agent.go

@@ -59,6 +59,10 @@ func agentCmd() {
 				modelOverride = args[i+1]
 				i++
 			}
+		default:
+			fmt.Printf("Unknown flag: %s\n", args[i])
+			fmt.Println("Run 'picoclaw agent --help' for usage.")
+			os.Exit(1)
 		}
 	}
 

cmd/picoclaw/cmd_auth.go

@@ -43,7 +43,11 @@ func authCmd() {
 }
 
 func authHelp() {
-	fmt.Println("\nAuth commands:")
+	fmt.Println("Usage: picoclaw auth <command>")
+	fmt.Println()
+	fmt.Println("Manage authentication credentials.")
+	fmt.Println()
+	fmt.Println("Commands:")
 	fmt.Println("  login       Login via OAuth or paste token")
 	fmt.Println("  logout      Remove stored credentials")
 	fmt.Println("  status      Show current auth status")
@@ -66,6 +70,9 @@ func authHelp() {
 	fmt.Println("  picoclaw auth models")
 	fmt.Println("  picoclaw auth logout --provider openai")
 	fmt.Println("  picoclaw auth status")
+	fmt.Println()
+	fmt.Println("Flags:")
+	fmt.Println("  -h, --help    Show this help")
 }
 
 func authLoginCmd() {

cmd/picoclaw/cmd_cron.go

@@ -72,6 +72,9 @@ func cronHelp() {
 	fmt.Println("  -d, --deliver     Deliver response to channel")
 	fmt.Println("  --to             Recipient for delivery")
 	fmt.Println("  --channel        Channel for delivery")
+	fmt.Println()
+	fmt.Println("Flags:")
+	fmt.Println("  -h, --help       Show this help")
 }
 
 func cronListCmd(storePath string) {

cmd/picoclaw/cmd_gateway.go

@@ -44,6 +44,10 @@ func gatewayCmd() {
 		case "--debug", "-d":
 			logger.SetLevel(logger.DEBUG)
 			fmt.Println("🔍 Debug mode enabled")
+		default:
+			fmt.Printf("Unknown flag: %s\n", arg)
+			fmt.Println("Run 'picoclaw gateway --help' for usage.")
+			os.Exit(1)
 		}
 	}
 

cmd/picoclaw/cmd_skills.go

@@ -16,8 +16,69 @@ import (
 	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
+func skillsCmd() {
+	if len(os.Args) < 3 {
+		skillsHelp()
+		return
+	}
+
+	subcommand := os.Args[2]
+
+	if subcommand == "--help" || subcommand == "-h" {
+		skillsHelp()
+		return
+	}
+
+	cfg, err := loadConfig()
+	if err != nil {
+		fmt.Printf("Error loading config: %v\n", err)
+		fmt.Println("Run 'picoclaw doctor' to check for common problems.")
+		os.Exit(1)
+	}
+
+	workspace := cfg.WorkspacePath()
+	installer := skills.NewSkillInstaller(workspace)
+	// Get global config dir and builtin skills dir
+	globalDir := filepath.Dir(getConfigPath())
+	globalSkillsDir := filepath.Join(globalDir, "skills")
+	builtinSkillsDir := filepath.Join(globalDir, "picoclaw", "skills")
+	skillsLoader := skills.NewSkillsLoader(workspace, globalSkillsDir, builtinSkillsDir)
+
+	switch subcommand {
+	case "list":
+		skillsListCmd(skillsLoader)
+	case "install":
+		skillsInstallCmd(installer, cfg)
+	case "remove", "uninstall":
+		if len(os.Args) < 4 {
+			fmt.Println("Usage: picoclaw skills remove <skill-name>")
+			return
+		}
+		skillsRemoveCmd(installer, os.Args[3])
+	case "install-builtin":
+		skillsInstallBuiltinCmd(workspace)
+	case "list-builtin":
+		skillsListBuiltinCmd()
+	case "search":
+		skillsSearchCmd(installer)
+	case "show":
+		if len(os.Args) < 4 {
+			fmt.Println("Usage: picoclaw skills show <skill-name>")
+			return
+		}
+		skillsShowCmd(skillsLoader, os.Args[3])
+	default:
+		fmt.Printf("Unknown skills command: %s\n", subcommand)
+		skillsHelp()
+	}
+}
+
 func skillsHelp() {
-	fmt.Println("\nSkills commands:")
+	fmt.Println("Usage: picoclaw skills <command>")
+	fmt.Println()
+	fmt.Println("Manage skills (install, list, remove).")
+	fmt.Println()
+	fmt.Println("Commands:")
 	fmt.Println("  list                    List installed skills")
 	fmt.Println("  install <repo>          Install skill from GitHub")
 	fmt.Println("  install-builtin         Install all builtin skills to workspace")
@@ -33,6 +94,9 @@ func skillsHelp() {
 	fmt.Println("  picoclaw skills list-builtin")
 	fmt.Println("  picoclaw skills remove weather")
 	fmt.Println("  picoclaw skills install --registry clawhub github")
+	fmt.Println()
+	fmt.Println("Flags:")
+	fmt.Println("  -h, --help    Show this help")
 }
 
 func skillsListCmd(loader *skills.SkillsLoader) {