cli: make bundled help self-describing

docs/inbox-cli.md

@@ -113,6 +113,15 @@ Rules:
 
 The binary name is `inbox`.
 
+Built-in help should be sufficient for first use:
+
+- root help should explain the worker role and the normal fetch -> claim -> update -> wait-reply -> done/fail loop
+- command help should explain when to use the command, not just list flags
+- high-frequency commands should include concrete examples that can be copied directly
+- `list` help should explain how it differs from `fetch`
+- `show` help should explain that it is the thread-history inspection command
+- `watch` help should explain how it differs from `wait-reply`
+
 ### Global Flags
 
 - `--db PATH`