cli: make bundled help self-describing

packages/inbox-runtime/internal/cli/inbox/root.go

@@ -14,8 +14,22 @@ func NewRootCmd() *cobra.Command {
 	opts := &rootOptions{}
 
 	cmd := &cobra.Command{
-		Use:           "inbox",
-		Short:         "Worker-facing durable coordination bus",
+		Use:   "inbox",
+		Short: "Worker-facing durable coordination bus",
+		Long: helpLong(
+			"Use inbox to coordinate durable worker-side execution through SQLite-backed threads, messages, leases, and artifacts.",
+			"Workers should use inbox directly to fetch or inspect one assigned thread, claim it, report progress, ask blocked questions, wait for answers, and finish with done or fail.",
+			"Leaders usually use orch for planning and dispatch, then use inbox mainly for inspection or manual repair.",
+			"fetch does not grant ownership; claim is the step that acquires the active lease.",
+		),
+		Example: `  inbox --db .agents/coord.db init
+  inbox --db .agents/coord.db fetch --agent worker-a --status pending
+  inbox --db .agents/coord.db claim --agent worker-a --thread thr_123
+  inbox --db .agents/coord.db show --thread thr_123
+  inbox --db .agents/coord.db update --agent worker-a --thread thr_123 --status in_progress --summary "Started work"
+  inbox --db .agents/coord.db update --agent worker-a --thread thr_123 --status blocked --summary "Need API decision" --payload-json '{"question":"Use v1 or v2?"}'
+  inbox --db .agents/coord.db wait-reply --thread thr_123 --after-event 10
+  inbox --db .agents/coord.db done --agent worker-a --thread thr_123 --summary "Finished"`,
 		SilenceErrors: true,
 		SilenceUsage:  true,
 	}