feat(mail): 프로젝트 메일 탭 — 고객사 도메인 메일 목록 + 메일별 공동 메모

- 프로젝트 상세에 '메일' 탭: @도메인과 주고받은 팀 메일 집계 목록(펼치면 본문·메모)
- 메일별 공동 메모(MailRow): 프로젝트 구성원 누구나 수정, 마지막 수정자 표시
- 연동 미설정/도메인 미입력 시 안내 EmptyState
- 프로젝트 생성·수정에 '고객사 메일 도메인' 입력 추가

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/api.ts

@@ -2,9 +2,9 @@ import axios from "axios";
 import type {
   Account, AcctSummary, ApprovalQueue, Attendance, AuditLog, ClientContact,
   Company, Contract, ContractFile, Dashboard, Department, DirectoryEntry, IncentiveConfig,
-  LeaveBalance, LeaveRequest, Me, Member, MyIncentive, NavItem, Notification,
+  LeaveBalance, LeaveRequest, MailNote, Me, Member, MyIncentive, NavItem, Notification,
-  OvertimeRequest, PaymentSplit, PaymentStage, Product, Project, ProjectMember,
+  OvertimeRequest, PaymentSplit, PaymentStage, Product, Project, ProjectMailsResponse,
-  ProjectTask, Settlement, SimResult, TaskComment, TaxRecord, Timesheet, Transaction,
+  ProjectMember, ProjectTask, Settlement, SimResult, TaskComment, TaxRecord, Timesheet, Transaction,
   UserIncentive, Version, WorkPolicy, WorkStatusEvent, WorkStatusKind,
 } from "@/types";
 
@@ -142,6 +142,13 @@ export const updateTask = (tId: string, b: Partial<ProjectTask>) =>
   api.patch<ProjectTask>(`/tasks/${tId}`, b).then((r) => r.data);
 export const deleteTask = (tId: string) => api.delete(`/tasks/${tId}`).then((r) => r.data);
 
+export const getProjectMails = (id: string) =>
+  api.get<ProjectMailsResponse>(`/projects/${id}/mails`).then((r) => r.data);
+export const getMailNotes = (id: string) =>
+  api.get<MailNote[]>(`/projects/${id}/mail-notes`).then((r) => r.data);
+export const putMailNote = (id: string, messageId: string, body: string) =>
+  api.put<MailNote>(`/projects/${id}/mail-notes`, { messageId, body }).then((r) => r.data);
+
 export const getTaskComments = (tId: string) =>
   api.get<TaskComment[]>(`/tasks/${tId}/comments`).then((r) => r.data);
 export const createTaskComment = (tId: string, body: string) =>

src/pages/ProjectDetail.tsx

@@ -3,11 +3,13 @@ import { useParams, Link } from "react-router-dom";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import {
   ArrowLeft, Plus, GanttChartSquare, Columns3, CalendarDays, Trash2, Upload, Download, Lock, Pencil,
+  Mail, ChevronDown, ChevronRight,
 } from "lucide-react";
 import {
   getProject, getProjectMembers, getContacts, getTasks, getContract, getContractFiles,
   getPayments, upsertProjectMember, deleteProjectMember, createTask, updateTask, deleteTask,
   getTaskComments, createTaskComment, deleteTaskComment,
+  getProjectMails, getMailNotes, putMailNote,
   upsertContact, deleteContact, putContract, uploadContractFile, getFileDownloadUrl,
   deleteContractFile, createPayment, updatePayment, deletePayment, recomputeProject,
   updateProject,
@@ -26,7 +28,7 @@ import {
   formatDate, formatDateTime, formatWon, formatSize, PROJECT_STATUS_META, LANE_LABELS,
   PRIORITY_META, classNames,
 } from "@/lib/format";
-import type { Lane, PaymentSplit, Project, ProjectTask, TaskPriority } from "@/types";
+import type { Lane, MailNote, PaymentSplit, Project, ProjectMail, ProjectTask, TaskPriority } from "@/types";
 
 export function ProjectDetailPage() {
   const { id = "" } = useParams();
@@ -44,6 +46,7 @@ export function ProjectDetailPage() {
     { key: "overview", label: "개요" },
     { key: "members", label: "작업자" },
     { key: "timeline", label: "타임라인" },
+    { key: "mail", label: "메일" },
     { key: "contacts", label: "업체 담당자" },
     ...(isAdmin ? [{ key: "contract", label: "계약 · 정산" }] : []),
   ];
@@ -63,6 +66,7 @@ export function ProjectDetailPage() {
           {tab === "overview" && <Overview project={p} />}
           {tab === "members" && <Members projectId={id} isAdmin={isAdmin} />}
           {tab === "timeline" && <Timeline projectId={id} isAdmin={isAdmin} />}
+          {tab === "mail" && <MailTab projectId={id} />}
           {tab === "contacts" && <Contacts projectId={id} isAdmin={isAdmin} />}
           {tab === "contract" && isAdmin && <ContractTab projectId={id} />}
         </div>
@@ -478,6 +482,91 @@ function Contacts({ projectId, isAdmin }: { projectId: string; isAdmin: boolean
   );
 }
 
+/* ---- project mail (Google Workspace) + 공동 메모 ---- */
+function MailTab({ projectId }: { projectId: string }) {
+  const { nameOf } = useDirectory();
+  const q = useQuery({ queryKey: ["mails", projectId], queryFn: () => getProjectMails(projectId) });
+  const notesQ = useQuery({ queryKey: ["mail-notes", projectId], queryFn: () => getMailNotes(projectId) });
+  const noteByMsg = new Map((notesQ.data ?? []).map((n) => [n.messageId, n]));
+
+  if (q.isLoading) return <LoadingState />;
+  const data = q.data;
+  if (!data?.enabled) {
+    return <EmptyState title="메일 연동이 설정되지 않았습니다" icon={<Mail size={28} />}
+      description="관리자가 Google Workspace 서비스계정(도메인 위임)을 연결하면, 이 프로젝트 고객사 도메인과 주고받은 메일이 팀 메일함에서 모여 표시됩니다." />;
+  }
+  if (!data.domain) {
+    return <EmptyState title="고객사 메일 도메인이 없습니다" icon={<Mail size={28} />}
+      description="‘프로젝트 수정’에서 고객사 메일 도메인(예: meditech.com)을 입력하면 관련 메일을 모아 봅니다." />;
+  }
+  return (
+    <div>
+      <div className="flex items-center justify-between mb-3 gap-2 flex-wrap">
+        <p className="text-sm text-ink-secondary">
+          <span className="font-medium text-ink">@{data.domain}</span> 와(과) 주고받은 메일 · 프로젝트 팀 메일함 집계
+        </p>
+        {data.error && <span className="text-xs text-status-pending-fg">일부 메일함을 읽지 못했습니다</span>}
+      </div>
+      {data.messages.length === 0 ? (
+        <EmptyState title="해당 도메인 메일이 없습니다" icon={<Mail size={28} />} description="팀 구성원이 이 고객사 도메인과 주고받은 메일이 없습니다." />
+      ) : (
+        <div className="space-y-2">
+          {data.messages.map((m) => (
+            <MailRow key={m.id} projectId={projectId} mail={m} note={noteByMsg.get(m.id)} nameOf={nameOf} />
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}
+
+function MailRow({ projectId, mail, note, nameOf }: { projectId: string; mail: ProjectMail; note?: MailNote; nameOf: (e?: string | null) => string }) {
+  const qc = useQueryClient();
+  const [open, setOpen] = useState(false);
+  const [memo, setMemo] = useState(note?.body ?? "");
+  useEffect(() => { setMemo(note?.body ?? ""); }, [note?.updatedAt]);
+  const save = useMutation({
+    mutationFn: () => putMailNote(projectId, mail.id, memo),
+    onSuccess: () => qc.invalidateQueries({ queryKey: ["mail-notes", projectId] }),
+  });
+  const when = mail.ts ? formatDateTime(new Date(mail.ts).toISOString()) : mail.date;
+
+  return (
+    <Card className="overflow-hidden">
+      <button onClick={() => setOpen((o) => !o)} className="w-full text-left flex items-start gap-3 px-4 py-3 hover:bg-canvas transition-colors">
+        <span className="mt-0.5 text-ink-muted shrink-0">{open ? <ChevronDown size={16} /> : <ChevronRight size={16} />}</span>
+        <span className="min-w-0 flex-1">
+          <span className="flex items-center gap-2">
+            <span className="text-sm font-semibold text-ink truncate">{mail.subject || "(제목 없음)"}</span>
+            {note?.body && <span className="text-[10px] bg-chip-bg text-navy rounded-pill px-1.5 py-0.5 shrink-0">메모</span>}
+          </span>
+          <span className="block text-xs text-ink-muted truncate mt-0.5">{mail.from}</span>
+          <span className="block text-sm text-ink-secondary truncate mt-1">{mail.snippet}</span>
+        </span>
+        <span className="text-[11px] text-ink-muted tabular shrink-0">{when}</span>
+      </button>
+      {open && (
+        <div className="px-4 pb-4 pt-1 border-t border-divider space-y-3">
+          <div className="text-xs text-ink-muted grid grid-cols-1 sm:grid-cols-2 gap-x-6 gap-y-1">
+            <div><span className="text-ink-secondary font-medium">보낸사람</span> {mail.from}</div>
+            <div><span className="text-ink-secondary font-medium">받는사람</span> {mail.to}</div>
+            <div className="sm:col-span-2"><span className="text-ink-secondary font-medium">발견된 메일함</span> {nameOf(mail.mailbox)} <span className="text-ink-muted">({mail.mailbox})</span></div>
+          </div>
+          <div>
+            <div className="flex items-center justify-between mb-1">
+              <span className="form-label !mb-0">공동 메모 <span className="text-ink-muted font-normal">· 프로젝트 구성원 누구나 수정</span></span>
+              {note?.lastEditedBy && <span className="text-[11px] text-ink-muted">마지막 수정 {nameOf(note.lastEditedBy)}</span>}
+            </div>
+            <Textarea value={memo} onChange={(e) => setMemo(e.target.value)}
+              onBlur={() => { if (memo !== (note?.body ?? "")) save.mutate(); }}
+              placeholder="이 메일에 대한 팀 메모를 남기세요. (대응 방향·할 일·합의 내용 등)" style={{ minHeight: 80 }} />
+          </div>
+        </div>
+      )}
+    </Card>
+  );
+}
+
 /* ---- contract / payments (ADMIN ONLY) ---- */
 function ContractTab({ projectId }: { projectId: string }) {
   const qc = useQueryClient();
@@ -604,7 +693,8 @@ function EditProjectModal({ project, onClose }: { project: Project; onClose: ()
   const [f, setF] = useState({
     name: project.name, consultingType: project.consultingType, country: project.country,
     scopeText: project.scopeText, scopeGraphic: project.scopeGraphic, pmEmail: project.pmEmail,
-    cautions: project.cautions, status: project.status, startDate: project.startDate, dueDate: project.dueDate,
+    clientDomain: project.clientDomain, cautions: project.cautions, status: project.status,
+    startDate: project.startDate, dueDate: project.dueDate,
   });
   const save = useMutation({
     mutationFn: () => updateProject(project.id, f as Partial<Project>),
@@ -631,6 +721,7 @@ function EditProjectModal({ project, onClose }: { project: Project; onClose: ()
           <Field label="시작일"><Input type="date" value={f.startDate} onChange={(e) => setF({ ...f, startDate: e.target.value })} /></Field>
           <Field label="마감일"><Input type="date" value={f.dueDate} onChange={(e) => setF({ ...f, dueDate: e.target.value })} /></Field>
         </div>
+        <Field label="고객사 메일 도메인" hint="이 도메인과 주고받은 메일을 '메일' 탭에 모아 봅니다. 예: meditech.com"><Input value={f.clientDomain} onChange={(e) => setF({ ...f, clientDomain: e.target.value })} placeholder="meditech.com" /></Field>
         <Field label="주의사항"><Textarea value={f.cautions} onChange={(e) => setF({ ...f, cautions: e.target.value })} /></Field>
       </div>
     </Modal>

src/pages/Projects.tsx

@@ -74,7 +74,7 @@ export function CreateProjectModal({ onClose }: { onClose: () => void }) {
   const [productId, setProductId] = useState("");
   const verQ = useQuery({ queryKey: ["versions", productId], queryFn: () => getVersions(productId), enabled: !!productId });
   const [versionId, setVersionId] = useState("");
-  const [form, setForm] = useState({ name: "", consultingType: "", country: "", scopeText: "", scopeGraphic: "", pmEmail: "", cautions: "", startDate: "", dueDate: "" });
+  const [form, setForm] = useState({ name: "", consultingType: "", country: "", scopeText: "", scopeGraphic: "", pmEmail: "", clientDomain: "", cautions: "", startDate: "", dueDate: "" });
 
   // quick-add master data
   const [newCompany, setNewCompany] = useState("");
@@ -149,6 +149,7 @@ export function CreateProjectModal({ onClose }: { onClose: () => void }) {
           <Field label="시작일"><Input type="date" value={form.startDate} onChange={(e) => setForm({ ...form, startDate: e.target.value })} /></Field>
           <Field label="마감일"><Input type="date" value={form.dueDate} onChange={(e) => setForm({ ...form, dueDate: e.target.value })} /></Field>
         </div>
+        <Field label="고객사 메일 도메인" hint="이 도메인과 주고받은 메일을 '메일' 탭에 모아 봅니다. 예: meditech.com"><Input value={form.clientDomain} onChange={(e) => setForm({ ...form, clientDomain: e.target.value })} placeholder="meditech.com" /></Field>
         <Field label="주의사항"><Textarea value={form.cautions} onChange={(e) => setForm({ ...form, cautions: e.target.value })} /></Field>
       </div>
     </Modal>

src/types.ts

@@ -185,6 +185,7 @@ export interface Project {
   scopeText: string;    // 글 계약 범위
   scopeGraphic: string; // 그림 계약 범위
   pmEmail: string;
+  clientDomain: string; // 고객사 메일 도메인(postfix)
   cautions: string;
   status: ProjectStatus;
   startDate: string;
@@ -193,6 +194,35 @@ export interface Project {
   updatedAt: string;
 }
 
+export interface ProjectMail {
+  id: string;
+  threadId: string;
+  from: string;
+  to: string;
+  subject: string;
+  date: string;
+  snippet: string;
+  mailbox: string;
+  ts: number;
+}
+
+export interface ProjectMailsResponse {
+  enabled: boolean;
+  domain: string;
+  messages: ProjectMail[];
+  error?: string;
+}
+
+export interface MailNote {
+  id: string;
+  projectId: string;
+  messageId: string;
+  body: string;
+  lastEditedBy: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
 export interface ProjectMember {
   id: string;
   projectId: string;