feat(external_imap): 强化 OAuth 外部邮箱授权校验并完善 Outlook 文案

- OAuth 授权改为以服务商返回的真实邮箱为准，补充 ID Token 解析与邮箱一致性校验，避免默认落到本地邮箱。
- 为 Gmail 和 Microsoft 365 / Outlook OAuth 增加必要的 OIDC scope，并补充相关测试覆盖。
- Web 端新增 OAuth 授权弹窗，支持填写外部邮箱与存储模式；同步更新账号展示信息。
- 同步修正 README 与部署说明中的 Outlook 表述。

README.md

@@ -158,7 +158,7 @@ docker compose -f docker-compose.yml -f docker-compose.build.yml up -d --build
 | `LANQIN_EXTERNAL_IMAP_SYNC_SECONDS` | 外部 IMAP 本地存储模式同步间隔 | `300` |
 | `LANQIN_EXTERNAL_IMAP_ALLOW_PRIVATE_HOSTS` | 是否允许外部 IMAP 连接内网/localhost 主机 | `false` |
 | `LANQIN_EXTERNAL_IMAP_GMAIL_CLIENT_ID` / `LANQIN_EXTERNAL_IMAP_GMAIL_CLIENT_SECRET` | Gmail 外部 IMAP OAuth2，回调为 `/api/external-imap-oauth/gmail/callback` | 空 |
-| `LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_ID` / `LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_SECRET` | Outlook 外部 IMAP OAuth2，回调为 `/api/external-imap-oauth/outlook/callback` | 空 |
+| `LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_ID` / `LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_SECRET` | Microsoft 365 / Outlook 外部 IMAP OAuth2，回调为 `/api/external-imap-oauth/outlook/callback` | 空 |
 
 ## 架构
 

apps/api/internal/app/app_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/emersion/go-sasl"
 	smtpclient "github.com/emersion/go-smtp"
 	"golang.org/x/crypto/bcrypt"
+	"golang.org/x/oauth2"
 )
 
 func newTestApp(t *testing.T) *App {
@@ -503,6 +504,102 @@ func TestExternalIMAPRejectsPrivateHostsByDefault(t *testing.T) {
 	}
 }
 
+func TestExternalIMAPOAuthStateDoesNotDefaultToLocalMailbox(t *testing.T) {
+	dir := t.TempDir()
+	a := newTestAppWithConfig(t, Config{
+		Addr:                            ":0",
+		DBPath:                          filepath.Join(dir, "lanqin.db"),
+		DataDir:                         filepath.Join(dir, "data"),
+		CookieName:                      "lanqin_test",
+		SessionTTLHours:                 24,
+		AdminEmail:                      "admin@lanqin.local",
+		AdminPassword:                   "ChangeMe123!",
+		PublicHostname:                  "mail.example.test",
+		PublicBaseURL:                   "http://localhost:5173",
+		AllowInsecureHTTP:               true,
+		ExternalIMAPSecretKey:           "test-secret",
+		ExternalIMAPOutlookClientID:     "client-id",
+		ExternalIMAPOutlookClientSecret: "client-secret",
+	})
+	ts := httptest.NewServer(a.Router())
+	defer ts.Close()
+	admin := &testClient{t: t, server: ts}
+	if code := admin.do("POST", "/api/auth/login", map[string]string{"email": "admin@lanqin.local", "password": "ChangeMe123!"}, nil); code != http.StatusOK {
+		t.Fatalf("login code=%d", code)
+	}
+	_, mb := defaultAdminUserAndMailbox(t, a)
+
+	var start struct {
+		URL string `json:"url"`
+	}
+	if code := admin.do("POST", "/api/me/external-imap-oauth/outlook/start", map[string]any{"mailboxId": mb.ID, "storageMode": "local", "syncReadState": true, "enabled": true}, &start); code != http.StatusOK {
+		t.Fatalf("start oauth code=%d url=%q", code, start.URL)
+	}
+	stateValue := mustOAuthStateFromURL(t, start.URL)
+	state, err := a.decryptExternalIMAPOAuthState(stateValue)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if state.Email != "" {
+		t.Fatalf("oauth state defaulted to local mailbox email: %q", state.Email)
+	}
+
+	if code := admin.do("POST", "/api/me/external-imap-oauth/outlook/start", map[string]any{"mailboxId": mb.ID, "email": "User@Example.COM", "storageMode": "remote", "syncReadState": true, "enabled": true}, &start); code != http.StatusOK {
+		t.Fatalf("start oauth with email code=%d url=%q", code, start.URL)
+	}
+	stateValue = mustOAuthStateFromURL(t, start.URL)
+	state, err = a.decryptExternalIMAPOAuthState(stateValue)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if state.Email != "user@example.com" {
+		t.Fatalf("oauth state did not preserve requested external email, got %q", state.Email)
+	}
+}
+
+func TestExternalIMAPOAuthEmailFromIDToken(t *testing.T) {
+	token := (&oauth2.Token{AccessToken: "access"}).WithExtra(map[string]any{
+		"id_token": testIDToken(map[string]any{"preferred_username": "User@Example.COM"}),
+	})
+	email, err := externalIMAPOAuthEmail(externalIMAPOAuthOutlook, token)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if email != "user@example.com" {
+		t.Fatalf("unexpected outlook oauth email %q", email)
+	}
+
+	token = (&oauth2.Token{AccessToken: "access"}).WithExtra(map[string]any{
+		"id_token": testIDToken(map[string]any{"email": "Person@Gmail.COM"}),
+	})
+	email, err = externalIMAPOAuthEmail(externalIMAPOAuthGmail, token)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if email != "person@gmail.com" {
+		t.Fatalf("unexpected gmail oauth email %q", email)
+	}
+}
+
+func mustOAuthStateFromURL(t *testing.T, rawURL string) string {
+	t.Helper()
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	state := u.Query().Get("state")
+	if state == "" {
+		t.Fatalf("oauth url missing state: %s", rawURL)
+	}
+	return state
+}
+
+func testIDToken(claims map[string]any) string {
+	header, _ := json.Marshal(map[string]any{"alg": "none"})
+	payload, _ := json.Marshal(claims)
+	return base64.RawURLEncoding.EncodeToString(header) + "." + base64.RawURLEncoding.EncodeToString(payload) + "."
+}
+
 func TestExternalIMAPAccountOwnershipIsolation(t *testing.T) {
 	dir := t.TempDir()
 	a := newTestAppWithConfig(t, Config{

apps/api/internal/app/external_imap.go

@@ -418,9 +418,10 @@ func (a *App) handleStartExternalIMAPOAuth(w http.ResponseWriter, r *http.Reques
 		respondError(w, http.StatusNotFound, "mailbox not found")
 		return
 	}
-	email := strings.TrimSpace(req.Email)
+	email := normalizeEmail(req.Email)
-	if email == "" {
+	if email != "" && !strings.Contains(email, "@") {
-		email = mb.Address
+		badRequest(w, errors.New("invalid oauth email"))
+		return
 	}
 	req.StorageMode = strings.ToLower(strings.TrimSpace(req.StorageMode))
 	if req.StorageMode == "" {
@@ -511,9 +512,18 @@ func (a *App) handleExternalIMAPOAuthCallback(w http.ResponseWriter, r *http.Req
 	if !token.Expiry.IsZero() {
 		expiry = token.Expiry.UTC().Format(time.RFC3339Nano)
 	}
+	authorizedEmail, err := externalIMAPOAuthEmail(provider, token)
+	if err != nil {
+		respondError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+	if state.Email != "" && !strings.EqualFold(normalizeEmail(state.Email), authorizedEmail) {
+		respondError(w, http.StatusBadRequest, "oauth account email does not match requested external email")
+		return
+	}
 	id := newID("ximap")
 	_, err = a.db.ExecContext(r.Context(), `INSERT INTO external_imap_accounts(id,user_id,mailbox_id,name,host,port,tls_mode,username,password_ciphertext,auth_mode,oauth_provider,oauth_email,oauth_access_token_ciphertext,oauth_refresh_token_ciphertext,oauth_expiry,storage_mode,sync_read_state,enabled,last_status,created_at,updated_at)
-		VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`, id, state.UserID, state.MailboxID, name, profile.Host, profile.Port, externalIMAPTLS, state.Email, "", externalIMAPAuthOAuth2, provider, state.Email, accessCipher, refreshCipher, expiry, state.StorageMode, boolInt(state.SyncReadState), boolInt(state.Enabled), "idle", now, now)
+		VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`, id, state.UserID, state.MailboxID, name, profile.Host, profile.Port, externalIMAPTLS, authorizedEmail, "", externalIMAPAuthOAuth2, provider, authorizedEmail, accessCipher, refreshCipher, expiry, state.StorageMode, boolInt(state.SyncReadState), boolInt(state.Enabled), "idle", now, now)
 	if err != nil {
 		respondError(w, http.StatusInternalServerError, "failed to save oauth account")
 		return
@@ -871,7 +881,7 @@ func (a *App) externalIMAPOAuthConfig(provider string) (*oauth2.Config, external
 			ClientID:     a.cfg.ExternalIMAPGmailClientID,
 			ClientSecret: a.cfg.ExternalIMAPGmailClientSecret,
 			RedirectURL:  callback,
-			Scopes:       []string{"https://mail.google.com/"},
+			Scopes:       []string{"openid", "email", "profile", "https://mail.google.com/"},
 			Endpoint: oauth2.Endpoint{
 				AuthURL:  "https://accounts.google.com/o/oauth2/v2/auth",
 				TokenURL: "https://oauth2.googleapis.com/token",
@@ -885,7 +895,7 @@ func (a *App) externalIMAPOAuthConfig(provider string) (*oauth2.Config, external
 			ClientID:     a.cfg.ExternalIMAPOutlookClientID,
 			ClientSecret: a.cfg.ExternalIMAPOutlookClientSecret,
 			RedirectURL:  callback,
-			Scopes:       []string{"offline_access", "https://outlook.office.com/IMAP.AccessAsUser.All"},
+			Scopes:       []string{"openid", "email", "profile", "offline_access", "https://outlook.office.com/IMAP.AccessAsUser.All"},
 			Endpoint: oauth2.Endpoint{
 				AuthURL:  "https://login.microsoftonline.com/common/oauth2/v2.0/authorize",
 				TokenURL: "https://login.microsoftonline.com/common/oauth2/v2.0/token",
@@ -896,6 +906,45 @@ func (a *App) externalIMAPOAuthConfig(provider string) (*oauth2.Config, external
 	}
 }
 
+func externalIMAPOAuthEmail(provider string, token *oauth2.Token) (string, error) {
+	if token == nil {
+		return "", errors.New("oauth token is missing")
+	}
+	idToken, _ := token.Extra("id_token").(string)
+	claims, err := externalIMAPOIDCClaims(idToken)
+	if err != nil {
+		return "", err
+	}
+	fields := []string{"email"}
+	if provider == externalIMAPOAuthOutlook {
+		fields = []string{"email", "preferred_username", "upn"}
+	}
+	for _, field := range fields {
+		value, _ := claims[field].(string)
+		email := normalizeEmail(value)
+		if email != "" && strings.Contains(email, "@") {
+			return email, nil
+		}
+	}
+	return "", errors.New("oauth provider did not return an email address")
+}
+
+func externalIMAPOIDCClaims(idToken string) (map[string]any, error) {
+	parts := strings.Split(idToken, ".")
+	if len(parts) < 2 {
+		return nil, errors.New("oauth provider did not return an id token")
+	}
+	payload, err := base64.RawURLEncoding.DecodeString(parts[1])
+	if err != nil {
+		return nil, errors.New("invalid oauth id token")
+	}
+	var claims map[string]any
+	if err := json.Unmarshal(payload, &claims); err != nil {
+		return nil, errors.New("invalid oauth id token")
+	}
+	return claims, nil
+}
+
 func (a *App) encryptExternalIMAPOAuthState(state externalIMAPOAuthState) (string, error) {
 	raw, err := json.Marshal(state)
 	if err != nil {

apps/web/src/lib/api-types.ts

@@ -125,7 +125,8 @@ export type BlockedSender = { id: string; mailboxId: string; email: string; reas
 export type MailStats = { totalMessages: number; unreadMessages: number; starredMessages: number; attachmentCount: number; attachmentBytes: number; storageBytes: number; quotaBytes: number; quotaUsedPct: number; byFolder: { folder: string; role: string; count: number; unread: number; bytes: number }[] }
 export type ExternalImapStorageMode = "local" | "remote"
 export type ExternalImapTlsMode = "tls" | "starttls" | "plain"
-export type ExternalImapAccount = { id: string; mailboxId: string; name: string; host: string; port: number; tlsMode: ExternalImapTlsMode; username: string; storageMode: ExternalImapStorageMode; syncReadState: boolean; enabled: boolean; lastSyncAt?: string; lastStatus: string; lastError?: string; createdAt: string; updatedAt: string }
+export type ExternalImapAuthMode = "password" | "oauth2"
+export type ExternalImapAccount = { id: string; mailboxId: string; name: string; host: string; port: number; tlsMode: ExternalImapTlsMode; username: string; authMode: ExternalImapAuthMode; oauthProvider?: ExternalImapOAuthProvider; oauthEmail?: string; oauthConfigured?: boolean; storageMode: ExternalImapStorageMode; syncReadState: boolean; enabled: boolean; lastSyncAt?: string; lastStatus: string; lastError?: string; createdAt: string; updatedAt: string }
 export type ExternalImapAccountPayload = { mailboxId: string; name: string; host: string; port: number; tlsMode: ExternalImapTlsMode; username: string; password?: string; storageMode: ExternalImapStorageMode; syncReadState: boolean; enabled: boolean }
 export type ExternalImapOAuthProvider = "gmail" | "outlook"
 export type ExternalImapOAuthStartPayload = { mailboxId: string; name?: string; email?: string; storageMode: ExternalImapStorageMode; syncReadState: boolean; enabled: boolean }

apps/web/src/pages/profile.tsx

@@ -239,7 +239,7 @@ export function ProfilePage() {
     onError: (error) => toast({ title: "同步失败", description: error.message }),
   })
   const startExternalOAuth = useMutation({
-    mutationFn: ({ provider, mailboxId }: { provider: ExternalImapOAuthProvider; mailboxId: string }) => api.startExternalImapOAuth(provider, { mailboxId, storageMode: "local", syncReadState: true, enabled: true }),
+    mutationFn: ({ provider, mailboxId, email, storageMode }: { provider: ExternalImapOAuthProvider; mailboxId: string; email: string; storageMode: ExternalImapStorageMode }) => api.startExternalImapOAuth(provider, { mailboxId, email, storageMode, syncReadState: true, enabled: true }),
     onSuccess: (res) => { window.location.href = res.url },
     onError: (error) => toast({ title: "授权失败", description: error.message }),
   })
@@ -353,7 +353,7 @@ export function ProfilePage() {
         onOpen={(id) => { if (!canAccessMail) return; setMailboxId(id); navigate("/") }}
         onApply={(payload) => applyMailbox.mutateAsync(payload).then(() => undefined)}
         onCreateExternal={(payload) => createExternalImap.mutate(payload)}
-        onStartExternalOAuth={(provider, mailboxId) => startExternalOAuth.mutate({ provider, mailboxId })}
+        onStartExternalOAuth={(provider, payload) => startExternalOAuth.mutate({ provider, ...payload })}
         onUpdateExternal={(id, payload) => updateExternalImap.mutate({ id, payload })}
         onDeleteExternal={(id) => deleteExternalImap.mutate(id)}
         onTestExternal={(id) => testExternalImap.mutate(id)}
@@ -592,7 +592,7 @@ function MailboxManagement({
   onOpen: (id: string) => void
   onApply: (payload: { domainId: string; localPart: string; displayName: string }) => Promise<void>
   onCreateExternal: (payload: ExternalImapAccountPayload) => void
-  onStartExternalOAuth: (provider: ExternalImapOAuthProvider, mailboxId: string) => void
+  onStartExternalOAuth: (provider: ExternalImapOAuthProvider, payload: { mailboxId: string; email: string; storageMode: ExternalImapStorageMode }) => void
   onUpdateExternal: (id: string, payload: ExternalImapAccountPayload) => void
   onDeleteExternal: (id: string) => void
   onTestExternal: (id: string) => void
@@ -618,8 +618,8 @@ function MailboxManagement({
               <div className="mt-1 text-sm text-muted-foreground">接入其他邮箱，可选择同步到本地，或每次打开时直接从远端读取。</div>
             </div>
             <div className="flex flex-wrap gap-2">
-              <Button type="button" variant="outline" disabled={!selectedMailbox || externalPending} onClick={() => onStartExternalOAuth("gmail", selectedMailboxId)}>Gmail OAuth</Button>
+              <ExternalImapOAuthDialog provider="gmail" selectedMailbox={selectedMailbox} disabled={!selectedMailbox} pending={externalPending} onStart={onStartExternalOAuth} />
-              <Button type="button" variant="outline" disabled={!selectedMailbox || externalPending} onClick={() => onStartExternalOAuth("outlook", selectedMailboxId)}>Outlook OAuth</Button>
+              <ExternalImapOAuthDialog provider="outlook" selectedMailbox={selectedMailbox} disabled={!selectedMailbox} pending={externalPending} onStart={onStartExternalOAuth} />
               <ExternalImapDialog mailboxId={selectedMailboxId} disabled={!selectedMailbox} pending={externalPending} onSubmit={onCreateExternal} />
             </div>
           </div>
@@ -638,7 +638,7 @@ function MailboxManagement({
                       <Badge variant={account.enabled ? "secondary" : "outline"}>{account.enabled ? "已启用" : "已停用"}</Badge>
                       <Badge variant="outline">{account.storageMode === "local" ? "本地存储" : "远端直连"}</Badge>
                     </div>
-                    <div className="mt-1 truncate text-xs text-muted-foreground">{account.username} · {account.host}:{account.port} · {account.tlsMode.toUpperCase()}</div>
+                    <div className="mt-1 truncate text-xs text-muted-foreground">{account.username} · {account.host}:{account.port} · {account.tlsMode.toUpperCase()}{account.authMode === "oauth2" ? ` · ${externalOAuthProviderLabel(account.oauthProvider)}` : ""}</div>
                     <div className="mt-1 text-xs text-muted-foreground">状态：{externalStatusLabel(account.lastStatus)}{account.lastSyncAt ? ` · 最近同步 ${formatDateTime(account.lastSyncAt)}` : ""}{account.lastError ? ` · ${account.lastError}` : ""}</div>
                   </div>
                   <div className="flex flex-wrap gap-2">
@@ -706,6 +706,50 @@ function ApplyMailboxDialog({ options, pending, onApply }: { options: MailboxApp
   )
 }
 
+
+function ExternalImapOAuthDialog({ provider, selectedMailbox, disabled, pending, onStart }: { provider: ExternalImapOAuthProvider; selectedMailbox?: Mailbox; disabled?: boolean; pending: boolean; onStart: (provider: ExternalImapOAuthProvider, payload: { mailboxId: string; email: string; storageMode: ExternalImapStorageMode }) => void }) {
+  const [open, setOpen] = React.useState(false)
+  const [storageMode, setStorageMode] = React.useState<ExternalImapStorageMode>("local")
+  const label = provider === "gmail" ? "Gmail OAuth" : "Microsoft 365 / Outlook OAuth"
+
+  function submit(event: React.FormEvent<HTMLFormElement>) {
+    event.preventDefault()
+    if (!selectedMailbox) return
+    const form = new FormData(event.currentTarget)
+    onStart(provider, {
+      mailboxId: selectedMailbox.id,
+      email: String(form.get("email") || ""),
+      storageMode,
+    })
+  }
+
+  return (
+    <Dialog open={open} onOpenChange={setOpen}>
+      <Button type="button" variant="outline" disabled={disabled || pending} onClick={() => setOpen(true)}>{label}</Button>
+      <DialogContent className="max-h-[92dvh] overflow-y-auto sm:max-w-lg">
+        <DialogHeader><DialogTitle>{label}</DialogTitle></DialogHeader>
+        <form className="space-y-4" onSubmit={submit}>
+          <div className="rounded-lg border bg-muted/30 p-3 text-sm text-muted-foreground">
+            OAuth 只适用于 {provider === "gmail" ? "Google Gmail" : "Microsoft 365 / Outlook / Exchange Online"} 托管邮箱。自建域名邮箱请使用“添加外部邮箱”的普通 IMAP 方式。
+          </div>
+          <Field label="外部邮箱地址（可选）"><Input name="email" type="email" placeholder={selectedMailbox?.address || "name@example.com"} /></Field>
+          <div className="text-xs text-muted-foreground">留空时会以 OAuth 服务商返回的真实授权邮箱为准；填写后，回调时会校验它和真实授权邮箱一致。</div>
+          <Field label="存储模式">
+            <Select value={storageMode} onValueChange={(value) => setStorageMode(value as ExternalImapStorageMode)}>
+              <SelectTrigger><SelectValue /></SelectTrigger>
+              <SelectContent><SelectItem value="local">同步到本地</SelectItem><SelectItem value="remote">远端直连</SelectItem></SelectContent>
+            </Select>
+          </Field>
+          <DialogFooter className="gap-2 [&>button]:w-full sm:[&>button]:w-auto">
+            <Button type="button" variant="outline" onClick={() => setOpen(false)}>取消</Button>
+            <Button disabled={pending || !selectedMailbox}>{pending ? "跳转中..." : "前往授权"}</Button>
+          </DialogFooter>
+        </form>
+      </DialogContent>
+    </Dialog>
+  )
+}
+
 function ExternalImapDialog({ account, mailboxId, disabled, pending, onSubmit }: { account?: ExternalImapAccount; mailboxId: string; disabled?: boolean; pending: boolean; onSubmit: (payload: ExternalImapAccountPayload) => void }) {
   const [open, setOpen] = React.useState(false)
   const [tlsMode, setTlsMode] = React.useState<ExternalImapTlsMode>(account?.tlsMode || "tls")
@@ -788,6 +832,10 @@ function externalStatusLabel(status: string) {
   return ({ idle: "未同步", ok: "正常", partial: "部分成功", error: "错误", running: "同步中" } as Record<string, string>)[status] || status || "未知"
 }
 
+function externalOAuthProviderLabel(provider?: ExternalImapOAuthProvider) {
+  return provider === "gmail" ? "Gmail OAuth" : provider === "outlook" ? "Microsoft 365 / Outlook OAuth" : "OAuth"
+}
+
 function ExternalImapSyncPanel({ account, folders, runs, pending, onSyncFolder }: { account: ExternalImapAccount; folders: ExternalImapFolder[]; runs: ExternalImapSyncRun[]; pending: boolean; onSyncFolder: (id: string, folder: string) => void }) {
   const [folder, setFolder] = React.useState("")
   React.useEffect(() => {

deploy/.env.example

@@ -145,7 +145,7 @@ LANQIN_EXTERNAL_IMAP_ALLOW_PRIVATE_HOSTS=false
 LANQIN_EXTERNAL_IMAP_GMAIL_CLIENT_ID=
 LANQIN_EXTERNAL_IMAP_GMAIL_CLIENT_SECRET=
 
-# Outlook 外部 IMAP OAuth2。回调地址：${LANQIN_PUBLIC_BASE_URL}/api/external-imap-oauth/outlook/callback
+# Microsoft 365 / Outlook 外部 IMAP OAuth2。回调地址：${LANQIN_PUBLIC_BASE_URL}/api/external-imap-oauth/outlook/callback
 LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_ID=
 LANQIN_EXTERNAL_IMAP_OUTLOOK_CLIENT_SECRET=
 

deploy/README.md

@@ -129,7 +129,7 @@ docker compose -f docker-compose.stack.yml -f docker-compose.stack.build.yml up
 - Go API 是 Webmail 和管理后台入口；浏览器不直接连接 SMTP/IMAP/POP3。
 - Go API 会读取 `LANQIN_MAILDIR_ROOT=/var/mail/vhosts`，周期扫描 Maildir，把 Postfix/Dovecot 入站邮件同步成 Webmail 索引。
 - 第三方客户端可通过 LanQin API 提供的 SMTP `465/587` 发信；Webmail/API 和第三方客户端的“已发送”都由 API 写入，外发投递进入发送队列并由 API worker relay/retry，客户端后续 IMAP APPEND 到 Sent 会按 `Message-ID` 去重。
-- 用户可在个人邮箱管理中接入外部 IMAP 账号；本地存储模式会同步到 LanQin，远端直连模式每次从远端读取。启用前必须配置 `LANQIN_EXTERNAL_IMAP_SECRET_KEY`，默认不允许连接 localhost / 内网 / link-local IMAP 主机。Gmail / Outlook OAuth2 需要在对应控制台配置回调地址：`/api/external-imap-oauth/gmail/callback` 或 `/api/external-imap-oauth/outlook/callback`。
+- 用户可在个人邮箱管理中接入外部 IMAP 账号；本地存储模式会同步到 LanQin，远端直连模式每次从远端读取。启用前必须配置 `LANQIN_EXTERNAL_IMAP_SECRET_KEY`，默认不允许连接 localhost / 内网 / link-local IMAP 主机。Gmail / Microsoft 365 / Outlook OAuth2 需要在对应控制台配置回调地址：`/api/external-imap-oauth/gmail/callback` 或 `/api/external-imap-oauth/outlook/callback`。
 - send-as v1 支持本人邮箱、启用的别名转发 source 指向本人邮箱，或数据库表 `send_as_grants` 中显式授权的地址。
 
 ## 邮件客户端 TLS 证书