Add get-code example and 2FA note

docs/README.md

@@ -0,0 +1,15 @@
+# SeedPass Documentation
+
+This directory contains supplementary guides for using SeedPass.
+
+## Quick Example: Get a TOTP Code
+
+Run `seedpass get-code` to retrieve a time-based one-time password (TOTP). A progress bar shows the remaining seconds in the current period.
+
+```bash
+$ seedpass get-code --index 0
+[##########----------] 15s
+Code: 123456
+```
+
+See [advanced_cli.md](advanced_cli.md) for a full command reference.