Added satty (Wayland-native screenshot annotation tool) and integrated it with the Capture flow.
Wired `$mod SHIFT, Print` to slurp a region and open satty.
Added "Annotate region" to the rofi Capture menu (Tools > Capture).
Added satty's configuration via home-manager to inject the active theme's palette colors into its UI.
Verified: V1 (flake check --no-build, home activation package build).
Pending: V3 hardware/visual check for the satty UI (queued in HARDWARE-QUEUE.md).
