feat(mail): 发信成功后归档到已发送（Sent）文件夹

Stalwart 不会自动把草稿移到 Sent，EmailSubmission 成功后显式 Email/set update mailboxIds 移至 Sent

src/utils/jmap.ts

@@ -151,6 +151,7 @@ export class JmapClient {
   }): Promise<void> {
     const mailboxes = await this.getMailboxes()
     const drafts = mailboxes.find((m) => m.role === 'drafts') || mailboxes[0]
+    const sent = mailboxes.find((m) => m.role === 'sent')
     const identityId = await this.getIdentityId()
 
     const emailData: Record<string, unknown> = {
@@ -188,12 +189,14 @@ export class JmapClient {
     ])
 
     const [, created] = result.methodResponses[0] || []
-    const createdData = created as unknown as { created?: Record<string, unknown> }
+    const createdData = created as unknown as { created?: Record<string, { id?: string }> }
     if (!createdData?.created) {
       const err = created as unknown as { notCreated?: Record<string, unknown> }
       const firstErr = Object.values(err.notCreated || {})[0] as { type?: string; description?: string } | undefined
       throw new Error(firstErr?.description || '创建邮件失败')
     }
+    const emailId = createdData.created.d1?.id
+    if (!emailId) throw new Error('创建邮件失败：未返回邮件 ID')
 
     // 检查 EmailSubmission/set 结果（methodResponses[1]）：Email/set 成功不代表已投递
     const [, submitted] = result.methodResponses[1] || []
@@ -202,5 +205,13 @@ export class JmapClient {
       const subErr = Object.values(submittedData?.notCreated || {})[0] as { type?: string; description?: string } | undefined
       throw new Error(subErr?.description || '邮件发送失败')
     }
+
+    // 发件成功后归档到「已发送」：Stalwart 不会自动把草稿移到 Sent，需显式移动
+    if (sent) {
+      await this.request([['Email/set', {
+        accountId: this.accountId,
+        update: { [emailId]: { mailboxIds: { [sent.id]: true } } },
+      }, 'c3']])
+    }
   }
 }