feat(mirada): mirada-layout — motor de teselado del compositor Wayland

Rect + split (reparto exacto de píxeles), 4 modos de layout
(MasterStack, Monocle, Grid, Columns) con tile(), y Workspace:
ventanas en orden de teselado, foco cíclico, reordenado y
resolución de geometría. Determinista, agnóstico de Wayland/smithay.

22 tests. #![forbid(unsafe_code)].

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Cargo.lock

@@ -7346,6 +7346,13 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "mirada-layout"
+version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "moka"
 version = "0.12.15"