feat 完善注释

src/composables/useCountDown.ts

@@ -1,6 +1,5 @@
 import { computed, onScopeDispose, ref } from 'vue'
 
-/** 倒计时（验证码 60s、二维码失效 4:32 等通用） */
 export function useCountDown(defaultSeconds = 60) {
   const seconds = ref(0)
   let timer: ReturnType<typeof setInterval> | null = null

src/composables/useIntersection.ts

@@ -1,6 +1,5 @@
 import { onMounted, onUnmounted, ref, type Ref } from 'vue'
 
-/** 元素可见性（配合图片懒加载/曝光统计） */
 export function useIntersection(
   target: Ref<Element | null | undefined>,
   options?: IntersectionObserverInit,

src/composables/useLoading.ts

@@ -1,6 +1,5 @@
 import { ref, type Ref } from 'vue'
 
-/** 请求 loading 状态管理 */
 export function useLoading(initial = false): {
   loading: Ref<boolean>
   withLoading: <T>(fn: () => Promise<T>) => Promise<T>

src/composables/useScroll.ts

@@ -1,6 +1,5 @@
 import { computed, onMounted, onUnmounted, ref, type ComputedRef, type Ref } from 'vue'
 
-/** 滚动监听/吸顶/回到顶部 */
 export function useScroll(threshold = 200): {
   scrollY: Ref<number>
   isAtTop: ComputedRef<boolean>