ci: give the ML4W dry-run job a simulated ML4W install

[Dreamcoder08]

Summary

The Full dry-run job of ML4W Setup Tests has failed on every run since at least July: its
pre-flight requires an ML4W install (Hyprland config is ML4W-managed) and the GitHub runner has
none. A workflow that is always red hides real regressions.

Changes

• Add a step that creates the two marker files the ownership predicates in lib/ml4w.sh look for
  (~/.config/hypr/conf/keybinding.lua and ~/.config/waybar/launch.sh) before the dry-runs.

Verification

Reproduced locally with a temporary HOME: without the step setup-hyprland.sh --profile default --dry-run exits 1; with it, setup-hyprland.sh and generate-custom-lua.sh dry-runs exit 0 for
both the default and asus-vivobook15 profiles.

Scope

• Includes: the workflow step only.
• Excludes: any change to the scripts or predicates. Independent of the stacked ML4W 2.16 PRs.