Add omarchy-mlx and omarchy-mlx-vulkan

Both packages come from one PKGBUILD, so the MLX wheel and the Vulkan
driver it was qualified on publish together.

omarchy-mlx-vulkan builds only the Honeykrisp Vulkan driver from
joshuaswarren/mesa-1 9b97b82ab1. It installs the driver, an ICD
manifest with an absolute library_path, and the driver's git SHA in
/usr/lib/omarchy-mlx/vulkan/. The manifest is outside the loader's
search path, so only omarchy-mlx uses the driver. It provides nothing
generic and conflicts with mesa-honeykrisp-omarchy.

omarchy-mlx builds the private venv offline from the release's
hash-locked vendor wheels and depends on the exact omarchy-mlx-vulkan
build.

The mlx-omarchy sources are placeholders until v0.7.7 is published.

pkgbuilds/omarchy-mlx/.omarchy/package.json

@@ -0,0 +1,11 @@
+{
+  "source": "local",
+  "channels": ["edge"],
+  "min_release_age": "24h",
+  "upstream": {
+    "watch": {
+      "github": "joshuaswarren/mlx-omarchy",
+      "pattern": "v(?P<version>[0-9]+(?:\\.[0-9]+)*)"
+    }
+  }
+}