feat: Improved lightness detection and media sharing controls, b=no-bug, c=media, workspaces

src/zen/workspaces/ZenGradientGenerator.mjs

@@ -1140,7 +1140,7 @@
     }
 
     shouldBeDarkMode(accentColor) {
-      let minimalLum = 0.5;
+      let minimalLum = 0.6;
       if (!this.canBeTransparent) {
         // Blend the color with the toolbar background
         const toolbarBg = this.getToolbarModifiedBaseRaw();

src/zen/workspaces/ZenWorkspaces.mjs

@@ -2944,4 +2944,10 @@ var gZenWorkspaces = new (class extends ZenMultiWindowFeature {
       gBrowser.tabContainer.removeAttribute('overflow');
     }
   }
+
+  handleTabCloseWindow() {
+    if (this.shouldCloseWindow()) {
+      document.getElementById('cmd_closeWindow').doCommand();
+    }
+  }
 })();