Start minimized to tray when launched at Windows login

[parkscloud]

Description

When I reboot my PC and log in, Printwell launches from the startup shortcut and opens its main window. I'd prefer it to start silently as a tray icon only, so the window doesn't appear until I explicitly open it from the tray.

Current behavior

• The installer registers a {commonstartup} shortcut via the startupicon task in installer.iss.
• On login, that shortcut runs Printwell.exe with no arguments.
• PrintwellApp.run() builds the MainWindow and calls _root.mainloop(), so the window is visible immediately.
• Every login I have to close the window to send it back to the tray.

Expected behavior

• When launched at startup, Printwell should appear only as a tray icon — no visible window.
• Clicking Open from the tray menu should show the window as it does today.
• Launching Printwell manually (Start Menu, desktop shortcut, or with a .md file argument) should still open the window as it does today.

Possible approaches

• Add a --minimized / --tray CLI flag; set Parameters: "--minimized" on the {commonstartup} entry in installer.iss; have app.py call self._root.withdraw() before mainloop() when the flag is present.
• Alternatively, always start withdrawn and only deiconify when a file argument is passed or the user opens the window from the tray.