perf: limit indexed cleanup task batches (#1107)

Limit mail, sent-mail, and indexed address cleanup to configurable batches. Includes E2E coverage and documentation.

vitepress-docs/docs/en/guide/worker-vars.md

@@ -103,6 +103,7 @@
 | `REMOVE_EXCEED_SIZE_ATTACHMENT` | Text/JSON | If attachment exceeds 2MB, remove it, email may lose some information due to parsing                                   | `true`                     |
 | `REMOVE_ALL_ATTACHMENT`         | Text/JSON | Remove all attachments, email may lose some information due to parsing                                                 | `true`                     |
 | `ENABLE_MAIL_GZIP`             | Text/JSON | When enabled, new emails are gzip-compressed and stored in `raw_blob` column to save D1 database space. Existing plaintext `raw` data is automatically compatible for reading. **Run database migration first (`Admin -> Quick Setup -> Database -> Migrate Database` or `POST /admin/db_migration`) to ensure the `raw_blob` column exists before enabling. This feature adds compression/decompression CPU overhead, so enabling it on a paid Cloudflare Worker plan is recommended.** | `true`                     |
+| `CLEANUP_BATCH_SIZE`           | Number    | Per-run limit for mail, sent-mail, and creation/activity-based address cleanup. Defaults to `3000`, valid range `1-5000`. Smaller values reduce per-run D1 pressure; larger values clear backlogs faster | `3000` |
 
 > [!NOTE]
 > Authentication results follow their standards: SPF `none` means no usable domain or SPF record was found, and SPF `neutral` must be treated like `none`; DKIM `none` means the message was unsigned, and DKIM `neutral` is also treated as unsigned; DMARC `none` means no applicable DMARC policy was found. Unregistered results and unsupported method versions are ignored. `JUNK_MAIL_CHECK_LIST` treats these results as absent, while `JUNK_MAIL_FORCE_PASS_LIST` still requires an explicit supported `pass`

vitepress-docs/docs/zh/guide/worker-vars.md

@@ -97,6 +97,7 @@
 | `REMOVE_EXCEED_SIZE_ATTACHMENT` | 文本/JSON | 如果附件大小超过 2MB，则删除附件，邮件可能由于解析而丢失一些信息           | `true`                     |
 | `REMOVE_ALL_ATTACHMENT`         | 文本/JSON | 移除所有附件，邮件可能由于解析而丢失一些信息                               | `true`                     |
 | `ENABLE_MAIL_GZIP`             | 文本/JSON | 启用后新邮件将 Gzip 压缩存储到 `raw_blob` 字段，可节省 D1 数据库空间。已有明文 `raw` 数据自动兼容读取。**启用前请先执行数据库迁移（`Admin -> 快速设置 -> 数据库 -> 升级数据库 Schema` 或 `POST /admin/db_migration`），确保 `raw_blob` 列已创建。该功能会增加压缩/解压 CPU 开销，建议使用 Cloudflare Worker 付费 Plan 再开启。** | `true`                     |
+| `CLEANUP_BATCH_SIZE`           | 数字      | 邮件、发件箱及按创建/活跃时间清理地址时的单次处理上限，默认 `3000`，有效范围 `1-5000`。较小值可降低单次 D1 压力，较大值可加快积压数据清理 | `3000` |
 
 > [!NOTE]
 > 认证结果遵循各自规范：SPF `none` 表示没有可检查的域名或 SPF 记录，SPF `neutral` 必须与 `none` 相同处理；DKIM `none` 表示邮件未签名，DKIM `neutral` 同样按未签名处理；DMARC `none` 表示没有适用的 DMARC 策略。未注册结果和不支持的方法版本也会被忽略。`JUNK_MAIL_CHECK_LIST` 将这些结果视为认证方法不存在，`JUNK_MAIL_FORCE_PASS_LIST` 仍只接受明确且受支持的 `pass`