fix(任务): 归档以整棵树为单位并移除隐藏中间态

- 自动归档改为 doneAt + autoArchive 到期，只判定顶层任务，到期整树归档
- 手动归档/恢复提升到根父任务，子任务完全跟随父任务
- 新增 normalizeArchiveTree 修复历史父子归档不一致
- 移除按列保留窗口的显示过滤（前后端实现删除，T-FL-01~15 废止）
- 列 retention 字段仅兼容旧数据保留，不再参与判定
- 已归档查询返回归档子任务，删除提示可正确显示连带条数

server/mcp/tools/tasks.js

@@ -17,7 +17,6 @@ import { tool, reqStr, parseMarkDate } from '../helpers.js'
 const MAX_NAME = 50
 const MAX_COLUMN_NAME = 20
 const STATUSES = ['todo', 'doing', 'done']
-const RETENTIONS = ['never', 'today', '3d', 'week', 'month', 'forever']
 
 const TASK_INCLUDE = {
   column: true,
@@ -294,16 +293,14 @@ function registerColumnTools(server, ctx) {
       projectId: z.coerce.number().int().positive().describe('项目 ID'),
       name: z.string().describe('列名, 最多 20 字'),
       boundStatus: z.enum(STATUSES).nullable().optional().describe('绑定任务状态 todo/doing/done, null 表示不联动'),
-      retention: z.enum(RETENTIONS).optional().describe('完成保留选项, 默认 forever'),
     },
-  }, async ({ projectId, name, boundStatus = null, retention = 'forever' }) => {
+  }, async ({ projectId, name, boundStatus = null }) => {
     const project = await requireProject(projectId, userId)
     const cleanName = reqStr(name, '列名', MAX_COLUMN_NAME)
     const cols = await loadColumns(project.id)
     if (cols.length >= MAX_COLUMNS) throw new Error(`最多 ${MAX_COLUMNS} 列`)
     if (cols.some((c) => c.name === cleanName)) throw new Error('列名已存在')
     if (boundStatus !== null && !STATUSES.includes(boundStatus)) throw new Error('绑定状态取值非法')
-    if (!RETENTIONS.includes(retention)) throw new Error('保留选项取值非法')
 
     const row = await prisma.boardColumn.create({
       data: {
@@ -312,7 +309,6 @@ function registerColumnTools(server, ctx) {
         name: cleanName,
         sortOrder: cols.length ? Math.max(...cols.map((c) => c.sortOrder)) + 1 : 0,
         boundStatus,
-        retention,
       },
     })
     return { item: row }
@@ -320,14 +316,13 @@ function registerColumnTools(server, ctx) {
 
   tool(server, 'update_column', {
     title: '修改看板列',
-    description: '修改列名、绑定状态或完成保留选项。',
+    description: '修改列名或绑定状态。',
     inputSchema: {
       columnId: z.coerce.number().int().positive().describe('看板列 ID'),
       name: z.string().optional().describe('新列名, 最多 20 字'),
       boundStatus: z.enum(STATUSES).nullable().optional().describe('绑定任务状态, null 表示取消绑定'),
-      retention: z.enum(RETENTIONS).optional().describe('完成保留选项'),
     },
-  }, async ({ columnId, name, boundStatus, retention }) => {
+  }, async ({ columnId, name, boundStatus }) => {
     const col = await prisma.boardColumn.findUnique({ where: { id: Number(columnId) } })
     if (!col) throw new Error('列不存在')
     const project = await requireProject(col.projectId, userId)
@@ -345,10 +340,6 @@ function registerColumnTools(server, ctx) {
       if (boundStatus !== null && !STATUSES.includes(boundStatus)) throw new Error('绑定状态取值非法')
       data.boundStatus = boundStatus
     }
-    if (retention !== undefined) {
-      if (!RETENTIONS.includes(retention)) throw new Error('保留选项取值非法')
-      data.retention = retention
-    }
     const row = await prisma.boardColumn.update({ where: { id: col.id }, data })
     return { item: row }
   })