重构：前端架构优化 - 消灭巨石文件，统一代码规范

Phase 1 - 消灭巨石页面：
- 拆分 AdminKuaishouCloudFulfillmentView (1,224行→kuaishou-cloud/子目录)
- 拆分 AdminFulfillmentBindingsView (989行→bindings/子目录)
- 拆分 AdminTaskDetailView (1,007行→9个子组件+2个composable)
- 合并去重 useClaimPage + useAdminManualRedeemPage (1,554行→共享模块+差异化薄层)
- 拆分 services/admin/platform-config.ts (477行→8个领域子模块)

Phase 2 - 架构收口：
- 拆分 types/admin.ts (925行→13个子文件+platform-config/子目录)
- 统一 API code 检查（http.ts拦截器统一处理业务错误）
- 修改 apiPost 签名消除 as unknown as 类型断言（6处）
- 新增 BusinessError 类型便于错误分类处理

所有改动通过 vue-tsc --noEmit 零错误和 vite build 验证

apps/frontend/src/composables/shared/useSessionQrDisplay.ts

@@ -0,0 +1,63 @@
+import { computed, ref, watch, type Ref, type ComputedRef } from 'vue'
+
+/**
+ * Shared QR code display logic: renders the base64 QR image, tracks its
+ * natural width after load, and derives display/preview widths.
+ */
+export function useSessionQrDisplay(options: {
+  session: ComputedRef<{ qrImageBase64?: string } | null>
+}) {
+  const { session } = options
+
+  const qrImageNaturalWidth = ref(0)
+
+  const qrImage = computed(() =>
+    session.value?.qrImageBase64 ? `data:image/png;base64,${session.value.qrImageBase64}` : '',
+  )
+
+  watch(qrImage, () => {
+    qrImageNaturalWidth.value = 0
+  })
+
+  function handleQrImageLoad(event: Event) {
+    const target = event.target
+
+    if (!(target instanceof HTMLImageElement)) {
+      return
+    }
+
+    qrImageNaturalWidth.value = target.naturalWidth || 0
+  }
+
+  const qrDisplayWidth = computed(() => {
+    const naturalWidth = qrImageNaturalWidth.value
+
+    if (!naturalWidth) {
+      return 220
+    }
+
+    if (naturalWidth < 160) {
+      return Math.min(naturalWidth * 2, 220)
+    }
+
+    return Math.min(naturalWidth, 240)
+  })
+
+  const qrFigureStyle = computed(() => ({
+    width: `${qrDisplayWidth.value}px`,
+    maxWidth: '100%',
+  }))
+
+  const qrPreviewWidth = computed(
+    () => `${Math.min(Math.max(qrDisplayWidth.value + 120, 360), 480)}px`,
+  )
+
+  return {
+    qrImage,
+    qrImageNaturalWidth,
+    qrDisplayWidth,
+    qrFigureStyle,
+    qrPreviewWidth,
+    handleQrImageLoad,
+  }
+}