Add README and MIT LICENSE

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

LICENSE

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+MIT License
+
+Copyright (c) 2026 Gavin Nugent
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# omalocal
+
+**One script that turns a stock Arch Linux ISO into a headless, key-only-SSH Arch
+*server* installer ISO** — one that, on first login, offers to bootstrap the
+[OMATERM](https://omaterm.org) terminal toolkit and [Once](https://once.com)
+(Basecamp's self-hosted app deployment platform). Burn it to a USB stick (Ventoy
+or `dd`) and you get a reproducible, minimal Arch server that's ready for
+self-hosting in minutes.
+
+> **Not affiliated with OMATERM or Once.** `omalocal` is an *ISO builder*. It
+> bundles and runs the official upstream installers; it does not vendor or fork
+> them.
+
+---
+
+## What you get
+
+Booting the generated ISO runs an automated installer that produces a **headless
+Arch Linux server**:
+
+- **UEFI-only**, systemd-boot, single 512 MB EFI partition + ext4 root.
+- **Key-only SSH** — your public key is baked in at build time; password auth and
+  root login over SSH are disabled.
+- **Reachable on the LAN as `<hostname>.local`** via Avahi/mDNS (`ssh you@host.local`).
+- **Docker** installed and enabled out of the box.
+- **ufw** firewall: deny incoming by default, allowing `22`, `80`, `443`,
+  `5353/udp` (mDNS) and `53317` (LocalSend).
+- On **first interactive login**, a one-time prompt offers to install Once,
+  [Omarchy-Send](https://github.com/28allday/omarchy-send) (optional), and
+  OMATERM — after which you're dropped straight into your new tmux session.
+- A small `once-mdns-sync` daemon that auto-publishes `<name>.local` for each
+  Once app you deploy, so they're reachable across the LAN with no per-app setup.
+
+---
+
+## Requirements (on the build machine)
+
+- A Linux box with: `xorriso`, `squashfs-tools`, `git`, `sha512sum`, `sudo`.
+- A **stock Arch ISO** (filename starting with `archlinux-`) from
+  <https://archlinux.org/download/>, placed next to the script.
+- An SSH public key (used for the headless server's only login method).
+
+## Build the ISO
+
+```sh
+# 1. Drop a stock Arch ISO into this folder:
+#      archlinux-x86_64.iso
+# 2. Run the builder (it needs sudo for squashfs work):
+./omalocal.sh
+# 3. Output:
+#      omalocal-arch-YYYYMMDD.iso   (Ventoy-compatible, dd-bootable)
+```
+
+By default the builder uses `~/.ssh/id_ed25519.pub` (falling back to
+`~/.ssh/id_rsa.pub`) as the server's authorized key. Override with:
+
+```sh
+SSH_PUBKEY=/path/to/key.pub ./omalocal.sh
+```
+
+## Install onto a machine
+
+Either drop `omalocal-arch-*.iso` onto a [Ventoy](https://www.ventoy.net/) USB,
+or write it to a stick directly:
+
+```sh
+sudo dd if=omalocal-arch-YYYYMMDD.iso of=/dev/sdX bs=4M status=progress conv=fsync
+```
+
+Boot the target in **UEFI** mode. The installer auto-starts on the console:
+it brings up networking (wired or Wi-Fi), prompts for hostname / user / password
+/ target disk (with a type-to-confirm guard before it wipes anything), installs
+the base system, and reboots into your headless server.
+
+## First login
+
+SSH in with the key you baked in:
+
+```sh
+ssh <user>@<hostname>.local
+```
+
+You'll be asked once whether to set the server up. Saying yes installs **Once**,
+optionally **Omarchy-Send**, then **OMATERM**, and leaves you in tmux.
+
+### Deploying a Once app reachable on the LAN
+
+Use the bundled `once-add` helper (single-label `.local` name, served over HTTP):
+
+```sh
+once-add                                    # interactive wizard
+once-add book ghcr.io/basecamp/writebook    # non-interactive
+# -> reachable at http://book.local from any machine on the LAN
+```
+
+---
+
+## How it works
+
+`omalocal.sh` is self-contained. It:
+
+1. Extracts `airootfs.sfs` from the stock ISO and unsquashes it.
+2. Injects an installer payload (auto-launched on `tty1`) plus your SSH key.
+3. Patches boot cmdlines (`rootdelay=60` for slow USB enumeration) and re-squashes.
+4. Repacks the ISO, preserving the stock boot config, hybrid MBR and volume UUID
+   so it stays bootable and Ventoy-friendly.
+
+The installed system's first-login helper, the LAN-deploy recipe, and a bundled
+Claude Code skill / `CLAUDE.md` are all embedded in the single script.
+
+## Notes & caveats
+
+- **UEFI only** — the installer aborts on legacy BIOS boot.
+- The installer **wipes the disk you select** (it asks you to type the path to
+  confirm). Double-check the target.
+- The build needs `sudo` to manipulate the squashfs image.
+
+## License
+
+MIT — see [`LICENSE`](LICENSE).