feat(notify): 站内通知与手工开单，指派/改状态/评论/验收都有人收到

M2 最后一块：让"该我办了"能出现在系统里，并且允许不经过任务直接开单。

通知（backend/app/services/notify.py 统一出口）
- 七类触发：task_assigned、task_status_changed、item_commented、
  ticket_assigned、ticket_submitted、ticket_approved/rejected、task_unblocked
- 不通知自己：notify() 按 actor_id 跳过，调用方不用各自判断
- 已读：GET /notifications、/unread-count、POST /read、/read-all

手工开单
- POST /tickets：直接指定人、初始 open，与任务升级单共用同一条 kind='ticket' item，
  ticket_ext.parent_item_id 为空，验收通过不回流任务
- 指派前 _ensure_member 校验在册成员，越界指派返回 1001（避免"挂在看不到的名字上"）

前端
- Web：通知页 /w/:wsId/notifications（未读/全部，点开标已读并跳目标）；
  工单页"新建"面板；AppShell 每 30 秒对未读数，标已读后 dispatch notifications:changed 立刻刷新；
  任务与工单支持 ?open= 深链落地即展开
- 安卓：五个 tab 加"通知"，未读数 30 秒刷新；工单动作按需求人/办理人/管理员显隐；手工开单对话框

验证
- pytest 85 passed（新增 backend/tests/test_notifications.py 6 个用例）
- ruff check / format --check 全 0
- tsc --noEmit 通过；vite build 成功
- web/e2e/notifications.mjs 12 项断言全绿（手工开单 → B 收到 → 点开跳转 → 未读归零）
- 安卓：本机 JDK 25 与 Gradle 8.7 / AGP 8.7.3 不兼容，本次未做编译验证，
  装回 JDK 17 后第一件事是 assembleDebug

web/src/pages/Tickets.tsx

@@ -1,12 +1,21 @@
 import { useCallback, useEffect, useRef, useState } from "react";
-import { useParams } from "react-router-dom";
+import { useParams, useSearchParams } from "react-router-dom";
 import { AppShell } from "../components/AppShell";
 import { TaskDetail } from "../components/TaskDetail";
-import { ChevronRight, TicketIcon } from "../components/icons";
-import { Button, EmptyState, InlineAlert, PageHeader, SkeletonRows, StatusPill } from "../components/ui";
+import { ChevronRight, Plus, TicketIcon } from "../components/icons";
+import {
+  Button,
+  EmptyState,
+  InlineAlert,
+  PageHeader,
+  Sheet,
+  SkeletonRows,
+  StatusPill,
+  useToast,
+} from "../components/ui";
 import { ApiError, api } from "../lib/client";
 import { STATUS_LABEL } from "../lib/parse";
-import type { Item, Ticket } from "../lib/types";
+import type { Item, Member, Ticket } from "../lib/types";
 
 const ROLES = [
   { key: "assigned", label: "派给我的", desc: "别人等你的" },
@@ -25,14 +34,43 @@ const STATUS_FILTERS = [
 
 export function TicketsPage() {
   const { wsId = "" } = useParams();
+  const [searchParams, setSearchParams] = useSearchParams();
   const [role, setRole] = useState<(typeof ROLES)[number]["key"]>("assigned");
   const [status, setStatus] = useState<string>("");
   const [tickets, setTickets] = useState<Ticket[]>([]);
   const [cursor, setCursor] = useState<string | null>(null);
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState<string | null>(null);
-  const [openId, setOpenId] = useState<string | null>(null);
+  // 从通知点进来时带 ?open=<id>，落地即展开那一条
+  const [openId, setOpenId] = useState<string | null>(searchParams.get("open"));
   const reqId = useRef(0);
+  const { push: toast } = useToast();
+
+  // 手工开单：这条路径不经过任何任务，所以人得自己选
+  const [members, setMembers] = useState<Member[]>([]);
+  const [creating, setCreating] = useState(false);
+  const [formTitle, setFormTitle] = useState("");
+  const [formBody, setFormBody] = useState("");
+  const [formAssignee, setFormAssignee] = useState("");
+  const [formPriority, setFormPriority] = useState(1);
+  const [formDue, setFormDue] = useState("");
+  const [saving, setSaving] = useState(false);
+
+  useEffect(() => {
+    if (!wsId) return;
+    let alive = true;
+    void api
+      .get<{ items: Member[] }>(`/workspaces/${wsId}/members?limit=100`)
+      .then((page) => {
+        if (alive) setMembers(page.items);
+      })
+      .catch(() => {
+        /* 成员拉不到时，表单里就没人可选，但不该拦住列表 */
+      });
+    return () => {
+      alive = false;
+    };
+  }, [wsId]);
 
   const load = useCallback(
     async (nextCursor: string | null) => {
@@ -75,7 +113,8 @@ export function TicketsPage() {
       void load(null);
     } catch (err) {
       if (err instanceof ApiError && err.code === 4009) {
-        setError("这条刚被别人改过，已为你刷新列表");        void load(null);
+        setError("这条刚被别人改过，已为你刷新列表");
+        void load(null);
         return;
       }
       setError(err instanceof ApiError ? err.message : "操作失败");
@@ -84,6 +123,41 @@ export function TicketsPage() {
 
   const currentRole = ROLES.find((r) => r.key === role);
 
+  async function createTicket() {
+    if (!formTitle.trim()) {
+      setError("工单得有个标题，别人才能知道要办什么");
+      return;
+    }
+    if (!formAssignee) {
+      setError("先选一个人——工单不指派就等于没人接");
+      return;
+    }
+    setSaving(true);
+    setError(null);
+    try {
+      const created = await api.post<Ticket>(`/workspaces/${wsId}/tickets`, {
+        title: formTitle.trim(),
+        body_md: formBody.trim() || null,
+        assignee_id: formAssignee,
+        priority: formPriority,
+        due_at: formDue ? new Date(formDue).toISOString() : null,
+      });
+      setCreating(false);
+      setFormTitle("");
+      setFormBody("");
+      setFormAssignee("");
+      setFormDue("");
+      setFormPriority(1);
+      setRole("requested");
+      toast("工单已开出，对方会收到通知", "success");
+      setOpenId(created.id);
+    } catch (err) {
+      setError(err instanceof ApiError ? err.message : "开单失败");
+    } finally {
+      setSaving(false);
+    }
+  }
+
   return (
     <AppShell wsId={wsId} active="tickets">
       <PageHeader
@@ -91,18 +165,24 @@ export function TicketsPage() {
         desc="待接 → 办理中 → 待验收 → 完成。验收通过后，当初卡住的那条任务会自动回到待办。"
         eyebrow={<>需要别人搭把手的事，都在这里</>}
         actions={
-          <select
-            className="input h-9 w-36 text-sm"
-            value={status}
-            onChange={(e) => setStatus(e.target.value)}
-            aria-label="按状态筛选"
-          >
-            {STATUS_FILTERS.map((s) => (
-              <option key={s.key} value={s.key}>
-                {s.label}
-              </option>
-            ))}
-          </select>
+          <>
+            <select
+              className="input h-9 w-36 text-sm"
+              value={status}
+              onChange={(e) => setStatus(e.target.value)}
+              aria-label="按状态筛选"
+            >
+              {STATUS_FILTERS.map((s) => (
+                <option key={s.key} value={s.key}>
+                  {s.label}
+                </option>
+              ))}
+            </select>
+            <Button variant="primary" size="sm" onClick={() => setCreating(true)}>
+              <Plus size={14} />
+              新建工单
+            </Button>
+          </>
         }
       />
 
@@ -218,11 +298,117 @@ export function TicketsPage() {
         </div>
       )}
 
+      {/* 手工开单：不经过任务，直接把一件要别人帮忙的事开成工单 */}
+      <Sheet
+        open={creating}
+        onClose={() => setCreating(false)}
+        title="新建工单"
+        subtitle="不是从任务升级来的也可以——写清楚要办什么，指定一个人。"
+        footer={
+          <>
+            <Button variant="ghost" onClick={() => setCreating(false)} disabled={saving}>
+              取消
+            </Button>
+            <Button variant="primary" onClick={() => void createTicket()} disabled={saving}>
+              {saving ? "正在开单…" : "开单并通知对方"}
+            </Button>
+          </>
+        }
+      >
+        <div className="space-y-5">
+          <div>
+            <label className="label" htmlFor="ticket-title">
+              要办什么
+            </label>
+            <input
+              id="ticket-title"
+              className="input"
+              value={formTitle}
+              onChange={(e) => setFormTitle(e.target.value)}
+              placeholder="一句能直接看懂的话，例如：核对 9 月发票与报销单"
+              maxLength={200}
+              autoFocus
+            />
+          </div>
+
+          <div>
+            <label className="label" htmlFor="ticket-body">
+              详细说明（可选）
+            </label>
+            <textarea
+              id="ticket-body"
+              className="input min-h-[96px] resize-y text-sm leading-6"
+              value={formBody}
+              onChange={(e) => setFormBody(e.target.value)}
+              placeholder="背景、已有的线索、验收标准…对方看到的就是这些"
+            />
+          </div>
+
+          <div className="grid gap-4 sm:grid-cols-2">
+            <div>
+              <label className="label" htmlFor="ticket-assignee">
+                交给谁
+              </label>
+              <select
+                id="ticket-assignee"
+                className="input"
+                value={formAssignee}
+                onChange={(e) => setFormAssignee(e.target.value)}
+              >
+                <option value="">选择一个人…</option>
+                {members.map((m) => (
+                  <option key={m.user_id} value={m.user_id}>
+                    {m.nickname || m.user_id.slice(0, 8)}
+                  </option>
+                ))}
+              </select>
+            </div>
+            <div>
+              <label className="label" htmlFor="ticket-priority">
+                优先级
+              </label>
+              <select
+                id="ticket-priority"
+                className="input"
+                value={formPriority}
+                onChange={(e) => setFormPriority(Number(e.target.value))}
+              >
+                <option value={0}>无</option>
+                <option value={1}>低</option>
+                <option value={2}>中</option>
+                <option value={3}>高</option>
+              </select>
+            </div>
+          </div>
+
+          <div>
+            <label className="label" htmlFor="ticket-due">
+              希望什么时候办好（可选）
+            </label>
+            <input
+              id="ticket-due"
+              type="datetime-local"
+              className="input"
+              value={formDue}
+              onChange={(e) => setFormDue(e.target.value)}
+            />
+          </div>
+
+          <p className="rounded-xl border border-line-200 bg-paper-200/60 px-3.5 py-2.5 text-2xs leading-5 text-ink-500">
+            开出后对方会收到通知，并按「待接 → 办理中 → 待验收 → 完成」推进。
+            手工开的单没有来源任务，验收通过后不会回流任何任务，但同样会沉淀一份知识草稿。
+          </p>
+        </div>
+      </Sheet>
+
       {openId && (
         <TaskDetail
           wsId={wsId}
           itemId={openId}
-          onClose={() => setOpenId(null)}
+          onClose={() => {
+            setOpenId(null);
+            if (searchParams.get("open")) setSearchParams({}, { replace: true });
+          }}
           onChanged={(updated: Item) =>
             setTickets((prev) => prev.map((t) => (t.id === updated.id ? { ...t, ...updated } : t)))
           }