收口前端平台组件库能力

新增 PlatformUiKit 通用弹窗、按钮、状态、空态、媒体、表单和标签等公共组件
迁移结果页、创作工作台、认证入口、RPG 暗色面板和运行态弹窗的重复 UI chrome
补充组件测试、页面回归测试、技术文档和 Hermes 共享决策记录

src/components/common/squareImageCropModel.ts

@@ -0,0 +1,46 @@
+export type SquareImageCropRect = {
+  x: number;
+  y: number;
+  size: number;
+};
+
+export function clampNumber(value: number, min: number, max: number) {
+  return Math.max(min, Math.min(max, value));
+}
+
+export function getSquareCropSizeBounds(imageSize: {
+  width: number;
+  height: number;
+}) {
+  const maxSize = Math.max(1, Math.min(imageSize.width, imageSize.height));
+  const minSize = Math.min(maxSize, Math.max(48, maxSize * 0.18));
+
+  return { minSize, maxSize };
+}
+
+export function buildCenteredSquareImageCropRect(imageSize: {
+  width: number;
+  height: number;
+}): SquareImageCropRect {
+  const size = Math.max(1, Math.min(imageSize.width, imageSize.height));
+
+  return {
+    x: Math.max(0, (imageSize.width - size) / 2),
+    y: Math.max(0, (imageSize.height - size) / 2),
+    size,
+  };
+}
+
+export function clampSquareImageCropRect(
+  imageSize: { width: number; height: number },
+  crop: SquareImageCropRect,
+): SquareImageCropRect {
+  const { minSize, maxSize } = getSquareCropSizeBounds(imageSize);
+  const size = clampNumber(crop.size, minSize, maxSize);
+
+  return {
+    x: clampNumber(crop.x, 0, Math.max(0, imageSize.width - size)),
+    y: clampNumber(crop.y, 0, Math.max(0, imageSize.height - size)),
+    size,
+  };
+}