docs: improve readme with developer pro-tips

README.md

@@ -73,6 +73,21 @@ infra cert renew
 - **Input Validation:** All IPs, MACs, and Ports are validated before execution.
 - **Pre-flight Checks:** The CLI verifies SSH connectivity to nodes before attempting changes.
 
+## Pro-Tips for Developers
+
+### Environment Selection
+- **Staging:** Use `--node la-vmh-07` for experiments.
+- **Public Production:** Use `--node la-vmh-12`.
+- **Private Production:** Use `--node la-vmh-13`.
+
+### Programmatic Integration
+The CLI is designed to be consumed by other scripts. Use the `--config` flag or `INFRA_CONFIG` environment variable to point to your configuration.
+
+```bash
+# Get just the IP for scripting
+NEW_IP=$(infra ip next-free)
+```
+
 ## Development
 
 ### Running Tests