packaging: adopt the phone deploy script and Arch PKGBUILD

Both were stranded untracked in the Pixel3Arch tree; they source from
this repo, so they live here. deploy-phone.sh ships the cross-built
binary + user unit (seed-id excluded, machine binding stays doctrine);
PKGBUILD builds from a synced local checkout, no network fetch.

packaging/arch/PKGBUILD

@@ -0,0 +1,38 @@
+# Maintainer: Fimeg <casey.tunturi@gmail.com>
+# Souveraine — sovereign agent substrate. Part of the SouveraineOS layer;
+# the phone runs the same server + agents as the desktop.
+pkgname=souveraine
+pkgver=0.1.0
+pkgrel=1
+pkgdesc="Sovereign agent substrate — server, TUI, surfaces"
+arch=('aarch64' 'x86_64')
+url="https://github.com/Fimeg/souveraine"
+license=('MIT')
+depends=('gcc-libs')
+makedepends=('cargo' 'git')
+options=('!lto')
+
+# Build from the local checkout synced by deploy-souveraine.sh (or a git
+# clone at /home/casey/souveraine-src on device). No network fetch — the
+# phone builds what the laptop ships.
+_srcdir="/home/casey/souveraine-src"
+
+pkgver() {
+    cd "$_srcdir"
+    git describe --tags --always 2>/dev/null | sed 's/^v//;s/-/./g' || echo "$pkgver"
+}
+
+build() {
+    cd "$_srcdir"
+    cargo build --release --locked
+}
+
+package() {
+    cd "$_srcdir"
+    install -Dm755 target/release/souveraine "$pkgdir/usr/bin/souveraine"
+    # repo unit points at ~/.local/bin (desktop dev install); packaged unit
+    # runs the pacman-owned binary
+    sed 's|%h/.local/bin/souveraine|/usr/bin/souveraine|' packaging/souveraine.service \
+        | install -Dm644 /dev/stdin "$pkgdir/usr/lib/systemd/user/souveraine.service"
+    install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
+}