Add per-window resize-margin override (Hyprland's extend_border_grab_area)

MISSING.md had listed this as needing to touch srdwm_core::window::
hit_test's signature at every call site, including the honest-stub
Windows/macOS backends - overstated on closer inspection: that shared
function already takes a plain resize_margin: i32 parameter, agnostic
to where the value comes from. The only real change needed was reading
Window.resize_margin.unwrap_or(wm-wide default) instead of always the
WM-wide value, at the single call site inside WindowManager::hit_test
in core - no backend touched at all.

Window.resize_margin: Option<i32>, WindowRuleActions.resize_margin to
match, applied in add_window/reapply_rules_if_pending the same way
opacity already is. Settable via a rule action or
srd.window.set_resize_margin(n) on the focused window.

1 files changed, 6 insertions, 0 deletions

diff --git a/crates/core/src/manager/windows.rs b/crates/core/src/manager/windows.rs
index 6171c15..4b4c0c8 100644
--- a/crates/core/src/manager/windows.rs
+++ b/crates/core/src/manager/windows.rs
@@ -52,6 +52,9 @@ impl WindowManager {
             if let Some(opacity) = a.opacity {
                 window.opacity = opacity.clamp(0.0, 1.0);
             }
+            if let Some(margin) = a.resize_margin {
+                window.resize_margin = Some(margin);
+            }
         }
 
         if let Some(monitor) = self.primary_monitor() {
@@ -127,6 +130,9 @@ impl WindowManager {
         if let Some(opacity) = actions.opacity {
             window.opacity = opacity.clamp(0.0, 1.0);
         }
+        if let Some(margin) = actions.resize_margin {
+            window.resize_margin = Some(margin);
+        }
         if let Some(geometry) = actions.geometry {
             window.geometry = geometry;
         }