config: add order rule for layers (#7697)

src/desktop/LayerSurface.cpp

@@ -394,6 +394,11 @@ void CLayerSurface::applyRules() {
         } else if (rule.rule.starts_with("animation")) {
             CVarList vars{rule.rule, 2, 's'};
             animationStyle = vars[1];
+        } else if (rule.rule.starts_with("order")) {
+            CVarList vars{rule.rule, 2, 's'};
+            try {
+                order = std::stoi(vars[1]);
+            } catch (...) { Debug::log(ERR, "Invalid value passed to order"); }
         }
     }
 }

src/desktop/LayerSurface.hpp

@@ -55,6 +55,7 @@ class CLayerSurface {
     bool                       ignoreAlpha      = false;
     float                      ignoreAlphaValue = 0.f;
     bool                       dimAround        = false;
+    int64_t                    order            = 0;
 
     std::optional<std::string> animationStyle;