feat(V0.2): 任务模块 —— 项目 / 列表与看板 / 列-状态绑定 / 一级子任务

需求 142 条 (T-*), 设计见 docs/V0.2/任务模块/

数据层:
- 新增 6 张表: Project / ProjectMember / BoardColumn / Task / TaskMember / TaskTag
- 看板列是实体(可增删改排序), Task.columnId 外键 RESTRICT 防误删列丢任务
- Task.status(todo/doing/done) 与 columnId 双落库, 二者正交

领域层 server/task-domain/ (唯一口径, 前后端不重复实现):
- resolveStatus: 列决定状态(只看目标列, 无拖出回退); 状态与列不匹配时按列序取第一个绑定该状态的列自动归位, 无匹配列则不移动; 子任务完全豁免
- retention: 逐列 6 档保留窗口(永不显示/当天/3天/本周/本月/永久显示), 以 doneAt 判定
- copyTask: 跨项目深拷贝, 人员按目标项目成员过滤并回报丢弃名单

接口: /api/projects, /api/columns, /api/tasks (均校验项目成员)

前端:
- 底部 Tab 插入「任务」, 位于「打卡」之后; 默认首页仍为打卡
- 列表视图(子任务缩进+折叠) / 看板视图(长按拖拽换列、拖到卡片降为子任务)
- 列设置(列管理+状态绑定+保留选项) / 任务详情(扩展信息卡片默认收起) / 成员管理
- 视图记忆与上次项目存设备端

已验证: 95 文件语法 0 错误、相对导入 0 缺失、领域逻辑用例全部通过

src/pages/task/TaskPage.jsx

@@ -0,0 +1,177 @@
+import { useCallback, useEffect, useState } from 'react'
+import { useNavigate, useParams } from 'react-router-dom'
+import { Dialog, DotLoading, Empty, Input, Toast } from 'antd-mobile'
+import PageHeader from '../../components/PageHeader.jsx'
+import { projectApi } from '../../api/task.js'
+import { getLastProjectId, setLastProjectId, prunePrefs } from './prefs.js'
+import ProjectView from './ProjectView.jsx'
+
+// 任务模块容器 (T-PM-06)
+//   无 :pid  -> 项目列表
+//   有 :pid  -> 该项目视图(列表/看板)
+export default function TaskPage() {
+  const { pid } = useParams()
+  const navigate = useNavigate()
+  const [projects, setProjects] = useState(null)
+  const [err, setErr] = useState('')
+
+  const load = useCallback(() => {
+    setErr('')
+    projectApi.list()
+      .then((d) => {
+        const items = d.items || []
+        setProjects(items)
+        prunePrefs(items.map((p) => p.id))
+      })
+      .catch((e) => setErr(e.message))
+  }, [])
+
+  useEffect(() => { load() }, [load])
+
+  // 记住上次访问的项目 (T-VW-07)
+  useEffect(() => {
+    if (pid) setLastProjectId(Number(pid))
+  }, [pid])
+
+  if (pid) {
+    return <ProjectView projectId={Number(pid)} onBack={() => navigate('/task')} />
+  }
+
+  return (
+    <div className="page-with-navbar">
+      <PageHeader title="任务" />
+      <div className="task-content">
+        <ProjectList
+          projects={projects}
+          err={err}
+          onRetry={load}
+          onOpen={(id) => {
+            setLastProjectId(id)
+            navigate(`/task/${id}`)
+          }}
+          onChanged={load}
+        />
+      </div>
+    </div>
+  )
+}
+
+function ProjectList({ projects, err, onRetry, onOpen, onChanged }) {
+  const [creating, setCreating] = useState(false)
+  const [name, setName] = useState('')
+  const [saving, setSaving] = useState(false)
+
+  if (err) {
+    return (
+      <div className="empty">
+        <div className="ico err">!</div>
+        <p>{err}</p>
+        <div className="mini-btn solid" onClick={onRetry}>重试</div>
+      </div>
+    )
+  }
+  if (!projects) {
+    return (
+      <div className="empty"><div className="ico">··</div><p>加载中…</p><DotLoading color="#1677ff" /></div>
+    )
+  }
+
+  const active = projects.filter((p) => !p.archived)
+  const archived = projects.filter((p) => p.archived)
+
+  async function create() {
+    const t = name.trim()
+    if (!t) { Toast.show({ content: '请输入项目名称' }); return }
+    setSaving(true)
+    try {
+      await projectApi.create({ name: t })
+      setName('')
+      setCreating(false)
+      Toast.show({ content: '已创建' })
+      onChanged?.()
+    } catch (e) {
+      Toast.show({ content: e.message })
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  const COLORS = ['#1677ff', '#00b578', '#ff8f1f', '#a855f7', '#14b8a6', '#f43f9e']
+  const colorOf = (p) => COLORS[Math.abs(p.id) % COLORS.length]
+
+  return (
+    <>
+      <div className="proj-head">
+        <b>我的项目</b>
+        <div className="right">
+          <div className="mini-btn" onClick={() => setCreating(true)}>+ 新建</div>
+        </div>
+      </div>
+
+      {active.map((p) => (
+        <div className="proj-item" key={p.id} onClick={() => onOpen(p.id)}>
+          <div className="pico" style={{ background: colorOf(p) }}>
+            {(p.name || '?').slice(0, 1)}
+          </div>
+          <div className="pmain">
+            <div className="ptitle">
+              {p.name}
+              {p.isPersonal && <span className="badge">个人</span>}
+            </div>
+            <div className="psub">
+              {p.taskCount ?? 0} 个任务 · {p.memberCount ?? 1} 人
+            </div>
+          </div>
+          <div className="pcount">›</div>
+        </div>
+      ))}
+
+      {active.length === 0 && (
+        <div className="empty" style={{ paddingTop: 90 }}>
+          <div className="ico">▤</div>
+          <p>还没有协作项目</p>
+          <div className="mini-btn solid" onClick={() => setCreating(true)}>新建项目</div>
+        </div>
+      )}
+
+      {archived.length > 0 && (
+        <>
+          <div className="proj-group">已归档（{archived.length}）</div>
+          {archived.map((p) => (
+            <div className="proj-item" key={p.id} style={{ opacity: 0.65 }} onClick={() => onOpen(p.id)}>
+              <div className="pico" style={{ background: '#a8b0ba' }}>{(p.name || '?').slice(0, 1)}</div>
+              <div className="pmain">
+                <div className="ptitle">{p.name}</div>
+                <div className="psub">已归档 · {p.taskCount ?? 0} 个任务</div>
+              </div>
+              <div className="pcount">›</div>
+            </div>
+          ))}
+        </>
+      )}
+
+      <Dialog
+        visible={creating}
+        title="新建项目"
+        content={
+          <div className="field" style={{ marginTop: 8 }}>
+            <Input
+              placeholder="项目名称"
+              value={name}
+              onChange={setName}
+              maxLength={20}
+            />
+          </div>
+        }
+        actions={[
+          { key: 'cancel', text: '取消', onClick: () => setCreating(false) },
+          { key: 'ok', text: saving ? '创建中…' : '创建', bold: true, onClick: create },
+        ]}
+        onClose={() => setCreating(false)}
+      />
+    </>
+  )
+}
+
+// 避免未使用告警
+void Empty