implemented robust fuse mount

packaging/PKGBUILD

@@ -61,5 +61,10 @@ package() {
   install -Dm644 "packaging/io.narl.proton-drive-linux.svg" \
     "$pkgdir/usr/share/icons/hicolor/scalable/apps/io.narl.proton-drive-linux.svg"
 
+  # systemd user service that runs the auto-mount daemon. Enabled per-user by
+  # the GUI on login (`systemctl --user enable --now proton-drive.service`).
+  install -Dm644 "packaging/proton-drive.service" \
+    "$pkgdir/usr/lib/systemd/user/proton-drive.service"
+
   install -Dm644 "LICENSE" "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
 }

packaging/proton-drive.service

@@ -0,0 +1,19 @@
+[Unit]
+Description=Proton Drive Files-On-Demand mount
+Documentation=https://github.com/narl/proton-drive-linux
+# Tie the mount to the desktop session: start after it is up and stop with it.
+After=graphical-session.target
+PartOf=graphical-session.target
+
+[Service]
+Type=simple
+# The daemon waits for a stored login, mounts ~/ProtonDrive, and keeps it
+# mounted. SIGTERM (from `systemctl --user stop`) triggers a clean lazy unmount.
+ExecStart=/usr/bin/pdfs daemon
+Restart=on-failure
+RestartSec=3
+# Give the lazy unmount time to finish before SIGKILL.
+TimeoutStopSec=15
+
+[Install]
+WantedBy=default.target