Add opt-in automatic startup with Option-key override

[drdator]

Every launch currently requires clicking Launch Omarchy, even when the saved settings need no changes. This adds an opt-in Start automatically checkbox that starts the VM through the existing launch path without displaying the start menu.

Hold Option while opening the app to show the menu again and change settings or disable automatic startup. Both reset flags always open the confirmation flow. The hidden menu is brought forward for boot recovery, unavailable storage, launch validation failures, and recoverable startup errors.

Validation:

• make test passed. The existing staged-QEMU lock-inheritance check was skipped because this checkout has no built QEMU binary.
• The native suite passed with 207 tests, including coverage for preference persistence, the Option override, reset requests, other launch modes, and the checkbox/hidden launch path.
• git diff --check passed.

A complete modified app bundle has not been booted against a real VM, and the physical Option-key override has not been exercised through Finder.