Add bin/omarchy-pkgs release command

One-command releases for the omarchy + omarchy-settings pair:
  bin/omarchy-pkgs release v4.0.0 | latest | rc [--commit sha] [--base X.Y.Z]

Rewrites both PKGBUILDs in lockstep (same _tag/_commit/pkgver/sha256sums,
pkgrel reset to 1), normalizes upstream tag forms to the vercmp-safe
attached rcN convention, refuses downgrades against the published edge DB,
regenerates and verifies checksums from a cached mirror clone, commits and
pushes to master, and triggers the build host when OMARCHY_BUILD_HOST is
configured. RCs stay on edge; finals are promoted with bin/repo migrate.
Includes a self-test covering tag normalization and pacman ordering, and a
README runbook.

.gitignore

@@ -32,3 +32,5 @@ pkgbuilds/omazed/steps.txt
 pkgbuilds/symfony-cli/symfony*
 !pkgbuilds/symfony-cli/symfony-cli.install
 pkgbuilds/yay/yay/
+.srcdest/
+.build-host