feat(V0.2): 克隆卡片跟手浮层 + 列表组内排序 + 把手统一移到最左

- 浮层改为激活时克隆原卡片 (DOM clone, 淡化+投影) 挂 body 顶层,
  移动直接改 transform —— 替代蓝色信息条, 所见即所拖
- 任务列表支持组内排序: 拖到本组某行上/下半显示插入指示, 松手提交
  POST /projects/:id/tasks/reorder (顶层任务按展平顺序重写 sortOrder);
  拖到其他分组仍为换列
- ⠿ 把手统一移到卡片最左: 打卡 / 列表任务行 / 看板卡片 (看板新增把手
  即按即拖路径, 与列表同款 touchstart preventDefault 双保险)
- useColumnDrag onDrop 经 ref 桥接防陈旧闭包

src/pages/task/ProjectView.jsx

@@ -102,6 +102,28 @@ export default function ProjectView({ projectId, onProjectChanged, onProjectExit
     } catch { /* 已回滚并提示 */ }
   }
 
+  /** 组内拖动排序: 按分组顺序展平重写 sortOrder (只动顶层任务) */
+  const reorderTask = async (task, targetId, after) => {
+    const snapshot = tasks
+    const orderedCols = [...(columns || [])].sort((a, b) => a.sortOrder - b.sortOrder)
+    const groups = orderedCols.map((c) => (tasks || []).filter((t) => t.columnId === c.id)).filter((l) => l.length)
+    const g = groups.find((l) => l.some((t) => t.id === task.id))
+    if (!g) return
+    const rest = g.filter((t) => t.id !== task.id)
+    const ti = rest.findIndex((t) => t.id === targetId)
+    if (ti < 0) return
+    rest.splice(after ? ti + 1 : ti, 0, task)
+    const flat = groups.map((l) => (l === g ? rest : l)).flat()
+    const orderOf = new Map(flat.map((t, i) => [t.id, i]))
+    setTasks((prev) => (prev || []).map((t) => (orderOf.has(t.id) ? { ...t, sortOrder: orderOf.get(t.id) } : t)))
+    try {
+      await taskApi.reorder(projectId, flat.map((t) => t.id))
+    } catch (e) {
+      setTasks(snapshot)
+      Toast.show({ content: e.message || '排序保存失败' })
+    }
+  }
+
   /** 改状态 (T-BD-14~16) */
   const changeStatus = async (task, status) => {
     try {
@@ -222,6 +244,7 @@ export default function ProjectView({ projectId, onProjectChanged, onProjectExit
             onOpen={(t) => setOpenTask(t)}
             onMore={openTaskMenu}
             onMoveColumn={moveToColumn}
+            onReorder={reorderTask}
           />
         ) : (
           <BoardView