docs: fix misleading wording in tutorial CLI tip

The tip previously said secrets come "from your ~/.towlion.conf" but
only 2 of 4 secrets originate there; APP_DOMAIN comes from the CLI
argument and SERVER_SSH_KEY is read from the key file.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: baijum

docs/tutorial.md

@@ -171,7 +171,7 @@ In your forked repository on GitHub, go to **Settings > Secrets and variables >
 Optionally, add `PREVIEW_DOMAIN` (e.g., `example.com`) to enable preview environments for pull requests.
 
 !!! tip "CLI shortcut"
-    The `towlion secrets` command sets all four secrets from your `~/.towlion.conf`:
+    The `towlion secrets` command sets all required GitHub secrets using your local config and SSH key:
     ```bash
     towlion secrets my-app app.example.com
     towlion secrets my-app app.example.com --preview-domain example.com