Nightly update: Finder cleanup, smoother quitting, clearer downloads

This nightly focuses on reducing friction in two places where the app could feel rough during early startup and Finder-driven use.

What changed

Finder no longer shows a dead-end Transmute submenu when there is nothing actionable to do. If there are no direct transmutations and no useful cartridge suggestions, the Transmute item is hidden entirely.
Quitting during startup is now faster and less annoying. If MachineFabric has not yet reached its ready state after launch, the app quits immediately instead of asking for confirmation first.
The downloads experience is clearer on the website:
- the preferred PKG installer is highlighted automatically
- bundled cartridges included in PKG builds are shown directly on the downloads page
- installer presentation and site footer/header details are more consistent across pages
Startup tips shown in the app have been trimmed down to reduce noise during first run.

This is a nightly build intended for testing and feedback.
Some of the underlying work in this build is release and packaging plumbing, especially around bundled-cartridge visibility and package metadata.