feat(mail): 支持草稿与定时发送

- 新增草稿保存、草稿编辑/删除、定时发送列表与取消接口，并在后台加入待发送任务表与定时发送工作协程。
- 邮件撰写页支持草稿自动保存、定时发送弹窗、草稿入口识别，以及待发送视图与状态标记。
- 同步补充前端 API 类型与调用，并增加定时发送流程的后端测试。

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

@@ -15,6 +15,9 @@ export type DNSRecord = { type: string; name: string; value: string; ttl: number
 export type DNSCheckResult = { domain: string; status: string; checks: Record<string, { ok: boolean; message: string; found?: string[] }> }
 export type ListResponse<T> = { items: T[]; nextCursor?: string }
 export type SendPayload = { mailboxId?: string; to: string[]; cc: string[]; bcc: string[]; subject: string; text: string; html: string; attachments: { filename: string; contentType: string; contentBase64: string }[] }
+export type DraftPayload = Omit<SendPayload, "attachments"> & { attachments?: SendPayload["attachments"] }
+export type ScheduleSendPayload = SendPayload & { draftId?: string; sendAt: string }
+export type ScheduledSend = { id: string; mailboxId: string; draftId?: string; subject: string; to: string[]; snippet: string; sendAt: string; status: "pending" | "sending" | "sent" | "failed" | "cancelled"; error?: string; createdAt: string; updatedAt: string; sentAt?: string }
 export type Contact = { id: string; name: string; email: string; note: string; createdAt: string }
 export type MailSignature = { id: string; mailboxId: string; name: string; content: string; isDefault: boolean; createdAt: string; updatedAt: string }
 export type MailRuleCondition = { field: "from" | "to" | "subject" | "body"; operator: "contains" | "not-contains" | "equals" | "not-equals" | "starts-with" | "ends-with"; value: string }

apps/web/src/lib/api.ts

@@ -1,4 +1,4 @@
-import type { User, AdminUser, AdminOverview, Domain, Mailbox, Alias, MailFolder, Attachment, MailLabel, MailMessage, DNSRecord, DNSCheckResult, ListResponse, SendPayload, Contact, MailSignature, MailRule, MailRuleCondition, MailRuleAction, BlockedSender, MailStats, MailboxApplyOptions, MailTemplate, SystemSettings, SystemSettingsPayload, PublicSettings, LoginPayload, LoginResponse, RegisterPayload } from "./api-types"
+import type { User, AdminUser, AdminOverview, Domain, Mailbox, Alias, MailFolder, Attachment, MailLabel, MailMessage, DNSRecord, DNSCheckResult, ListResponse, SendPayload, DraftPayload, ScheduleSendPayload, ScheduledSend, Contact, MailSignature, MailRule, MailRuleCondition, MailRuleAction, BlockedSender, MailStats, MailboxApplyOptions, MailTemplate, SystemSettings, SystemSettingsPayload, PublicSettings, LoginPayload, LoginResponse, RegisterPayload } from "./api-types"
 export * from "./api-types"
 
 const REQUEST_TIMEOUT_MS = 15_000
@@ -121,6 +121,11 @@ export const api = {
   },
   message: (id: string, options: { markRead?: boolean } = {}) => request<MailMessage>(`/api/mail/messages/${id}${options.markRead === false ? "?markRead=0" : ""}`),
   send: (payload: SendPayload) => request<MailMessage>("/api/mail/send", { method: "POST", body: JSON.stringify(payload), timeoutMs: MAIL_DELIVERY_TIMEOUT_MS }),
+  scheduledSends: (mailboxId?: string) => request<ListResponse<ScheduledSend>>(`/api/mail/scheduled-sends${mailboxId ? `?mailboxId=${encodeURIComponent(mailboxId)}` : ""}`),
+  scheduleSend: (payload: ScheduleSendPayload) => request<ScheduledSend>("/api/mail/schedule-send", { method: "POST", body: JSON.stringify(payload), timeoutMs: MAIL_DELIVERY_TIMEOUT_MS }),
+  cancelScheduledSend: (id: string) => request<{ ok: boolean }>(`/api/mail/schedule-send/${id}`, { method: "DELETE" }),
+  saveDraft: (payload: DraftPayload, id?: string) => request<MailMessage>(id ? `/api/mail/drafts/${id}` : "/api/mail/drafts", { method: "POST", body: JSON.stringify(payload), timeoutMs: MAIL_DELIVERY_TIMEOUT_MS }),
+  deleteDraft: (id: string) => request<{ ok: boolean }>(`/api/mail/drafts/${id}`, { method: "DELETE" }),
   markRead: (id: string, read: boolean) => request<{ ok: boolean }>(`/api/mail/messages/${id}/mark-read`, { method: "POST", body: JSON.stringify({ read }) }),
   star: (id: string, starred: boolean) => request<{ ok: boolean }>(`/api/mail/messages/${id}/star`, { method: "POST", body: JSON.stringify({ starred }) }),
   addLabel: (id: string, payload: { name: string; color?: string }) => request<{ labels: MailLabel[] }>(`/api/mail/messages/${id}/labels`, { method: "POST", body: JSON.stringify(payload) }),