Record the boot recipes as manual holds and state pacman's repository order

A bare uboot-asahi comes from whichever repository is listed first, so the
comment now says when this build wins and when asahi-alarm's does.

pkgbuilds/uboot-asahi/.omarchy/package.json

@@ -1,4 +1,5 @@
 {
   "source": "local",
-  "channels": ["edge"]
+  "channels": ["edge"],
+  "sync": false
 }