Add omarchy-mac-boot for aarch64 edge

The Apple Silicon boot package (Mac initramfs, in-place encryption, first
boot and the Limine activation gate) now builds from packages/omarchy-mac/boot
in omacom/omarchy-mac at a pinned commit: the recipe runs the source's tests
and install staging, and keeps only metadata, backup= and the pacman
scriptlet from the fork recipe. aarch64 and edge only; 20260925-1 upgrades
the fork's 20260921-10. It needs the Apple-gated limine-mkinitcpio-hook
1.39.0-2.

pkgbuilds/omarchy-mac-boot/.omarchy/package.json

@@ -0,0 +1 @@
+{ "source": "local", "channels": ["edge"] }