CLI: improve command descriptions in help output (#18486)

* CLI: clarify config vs configure descriptions

* CLI: improve top-level command descriptions

* CLI: make direct command help more descriptive

* CLI: add commands hint to root help

* CLI: show root help hint in implicit help output

* CLI: add help example for command-specific help

* CLI: tweak root subcommand marker spacing

* CLI: mark clawbot as subcommand root in help

* CLI: derive subcommand markers from registry metadata

* CLI: escape help regex CLI name

src/cli/plugins-cli.ts

@@ -163,7 +163,7 @@ function logSlotWarnings(warnings: string[]) {
 export function registerPluginsCli(program: Command) {
   const plugins = program
     .command("plugins")
-    .description("Manage OpenClaw plugins/extensions")
+    .description("Manage OpenClaw plugins and extensions")
     .addHelpText(
       "after",
       () =>