packaging: one-shot dev-mount.sh for the live VM preview loop

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

packaging/dev-mount.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+# dev-mount.sh — one-shot dev-VM setup. Run via:
+#   curl -fsSL https://raw.githubusercontent.com/28allday/nosignal-shell/nosignal/packaging/dev-mount.sh | sudo sh
+#
+# Mounts the 9p `nsfork` share (the host's nosignal-shell fork) at /mnt/fork and
+# points the running shell at it (~/.config/quickshell/caelestia symlink), so
+# host-side QML edits + Ctrl+Super+Alt+R preview the layout live.
+set -eu
+
+modprobe 9pnet_virtio 2>/dev/null || true
+mkdir -p /mnt/fork
+if ! mountpoint -q /mnt/fork; then
+  mount -t 9p -o trans=virtio,version=9p2000.L,access=any nsfork /mnt/fork
+fi
+[ -e /mnt/fork/shell.qml ] || { echo "9p share mounted but shell.qml missing — wrong mount_tag?" >&2; exit 1; }
+
+# Symlink as the human user (this script runs as root via sudo).
+U="${SUDO_USER:-$(logname 2>/dev/null || true)}"
+[ -n "$U" ] || U=$(awk -F: '$3>=1000 && $3<60000 && $7 !~ /(nologin|false)$/ {print $1; exit}' /etc/passwd)
+H=$(getent passwd "$U" | cut -d: -f6)
+install -d -o "$U" -g "$U" "$H/.config/quickshell"
+if [ -e "$H/.config/quickshell/caelestia" ] && [ ! -L "$H/.config/quickshell/caelestia" ]; then
+  mv "$H/.config/quickshell/caelestia" "$H/.config/quickshell/caelestia.bak.$$"
+fi
+sudo -u "$U" ln -sfn /mnt/fork "$H/.config/quickshell/caelestia"
+
+echo ":: fork mounted at /mnt/fork"
+echo ":: ~$U/.config/quickshell/caelestia -> /mnt/fork (the host fork checkout)"
+echo ":: NOW reload the shell to load the fork:  Ctrl+Super+Alt+R"