feat(new_editor): add project panel and polish dock chrome

engine/include/XCEngine/UI/DrawData.h

@@ -31,6 +31,7 @@ enum class UIDrawCommandType : std::uint8_t {
     RectOutline,
     FilledRectLinearGradient,
     Line,
+    FilledTriangle,
     FilledCircle,
     CircleOutline,
     Text,
@@ -149,6 +150,20 @@ public:
         return AddCommand(std::move(command));
     }
 
+    UIDrawCommand& AddFilledTriangle(
+        const UIPoint& a,
+        const UIPoint& b,
+        const UIPoint& c,
+        const UIColor& color) {
+        UIDrawCommand command = {};
+        command.type = UIDrawCommandType::FilledTriangle;
+        command.position = a;
+        command.uvMin = b;
+        command.uvMax = c;
+        command.color = color;
+        return AddCommand(std::move(command));
+    }
+
     UIDrawCommand& AddFilledCircle(
         const UIPoint& center,
         float radius,