docs: add Get omalocal clone step to README

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -41,6 +41,15 @@ Arch Linux server**:
   <https://archlinux.org/download/>, placed next to the script.
 - An SSH public key (used for the headless server's only login method).
 
+## Get omalocal
+
+Clone the repo (only `omalocal.sh` and `LICENSE` are needed to build):
+
+```sh
+git clone https://github.com/28allday/omalocal.git
+cd omalocal
+```
+
 ## Build the ISO
 
 ```sh