pkg-snapshot: record user-scope flatpaks too

Moonlight went on the work laptop as a flatpak, which neither apt-mark nor
pacman can see — so a rebuild from the manifests would have silently left
it out. pkg-restore adds the flathub user remote before installing, since
Ubuntu ships flathub as a system remote that --user cannot resolve.

System-scope flatpaks are deliberately not recorded: those belong to
whoever administers the machine, not to these dotfiles.

common/bin/pkg-restore

@@ -14,3 +14,9 @@ elif [[ -f "${P}/${HOST}.apt" ]]; then
 else
   echo "pkg-restore: no manifest for '${HOST}' in ${P}" >&2; exit 1
 fi
+
+if [[ -f "${P}/${HOST}.flatpak" ]] && command -v flatpak >/dev/null 2>&1; then
+  flatpak remote-add --user --if-not-exists flathub \
+    https://dl.flathub.org/repo/flathub.flatpakrepo
+  xargs -r -a "${P}/${HOST}.flatpak" flatpak install -y --user flathub
+fi

common/bin/pkg-snapshot

@@ -18,3 +18,14 @@ elif command -v apt-mark >/dev/null 2>&1; then
 else
   echo "pkg-snapshot: no pacman or apt-mark on this machine" >&2; exit 1
 fi
+
+# Flatpaks are invisible to both package managers, so record them separately.
+# User-scope only: system-scope flatpaks belong to whoever administers the box.
+if command -v flatpak >/dev/null 2>&1; then
+  flatpak list --app --user --columns=application 2>/dev/null | LC_ALL=C sort > "${OUT}/${HOST}.flatpak"
+  if [[ -s "${OUT}/${HOST}.flatpak" ]]; then
+    echo "wrote ${HOST}.flatpak ($(wc -l < "${OUT}/${HOST}.flatpak"))"
+  else
+    rm -f "${OUT}/${HOST}.flatpak"
+  fi
+fi