docs(aur): add local amd64 Arch build runbook

RELEASE.md

@@ -48,6 +48,8 @@ Use `pnpm release:review --json` when automating these checks in scripts or agen
 
 `Release App` publishes the Arch AUR package automatically after the Linux `.deb` asset is uploaded.
 
+For local AMD64 Arch builds without Docker, see `packaging/aur/README.md`.
+
 Required repo config:
 
 - GitHub Actions secret: `AUR_SSH_PRIVATE_KEY` (SSH key with push access to the AUR package repo)

packaging/aur/README.md

@@ -0,0 +1,77 @@
+# Arch Linux AMD64 package
+
+Use this directory to build and install the AMD64 OpenWork package locally on Arch Linux without Docker.
+
+## What this packaging does
+
+- Targets `x86_64` Arch Linux.
+- Downloads the published GitHub release asset `openwork-desktop-linux-amd64.deb`.
+- Repackages the `.deb` contents into an Arch package with `makepkg`.
+
+## Prerequisites
+
+- Arch Linux on `x86_64`
+- `base-devel`
+- `bsdtar` / `libarchive`
+- `curl`
+
+Install the packaging prerequisites once:
+
+```bash
+sudo pacman -S --needed base-devel curl libarchive
+```
+
+## Build and install the current packaged version
+
+From the repo root:
+
+```bash
+cd packaging/aur
+makepkg -si
+```
+
+That will:
+
+1. download the AMD64 `.deb` pinned in `PKGBUILD`
+2. build an Arch package such as `openwork-<version>-1-x86_64.pkg.tar.zst`
+3. install it locally with `pacman`
+
+## Update the package to a newer release
+
+If the GitHub release version changed, refresh the packaging metadata first:
+
+```bash
+scripts/aur/update-aur.sh v0.11.162
+```
+
+Then rebuild:
+
+```bash
+cd packaging/aur
+makepkg -si
+```
+
+## Build without installing
+
+```bash
+cd packaging/aur
+makepkg -s
+```
+
+This leaves the built package in `packaging/aur/` so you can install it later with:
+
+```bash
+sudo pacman -U openwork-<version>-1-x86_64.pkg.tar.zst
+```
+
+## Verify the installed app
+
+```bash
+openwork
+```
+
+If you want to confirm the package contents first:
+
+```bash
+pacman -Ql openwork
+```