feat(clients): support setting HWID limit and MTProto ad-tag in bulk adjust (#6399)

* feat(clients): support setting HWID limit and MTProto ad-tag in bulk adjust

Add HWID device limit and Telegram MTProto sponsor channel (ad-tag)
support to the bulk client adjustment flow in both the panel API
and frontend ClientBulkAdjustModal.

Co-Authored-By: Claude Code <noreply@anthropic.com>

* fix(clients): gate adTag to MTProto inbounds and avoid inbound rewrite for limitHwid

Co-Authored-By: Claude Code <noreply@anthropic.com>

* fix(clients): stamp updated_at only on the clients a bulk adjust changed

The updated_at write was gated on hasInboundChanges, which accumulates
over the whole inbound instead of describing the client in hand. Once any
client in the settings array changed, every client after it was re-stamped
as well, so whether an untouched client kept its own updated_at depended on
its position in the array. That field feeds node-snapshot conflict
resolution, where a spurious bump lets a stale snapshot value win over the
stored record.

Track the change per client and fold it into the inbound-level flag where
the stamp is written, so the early return still skips a save whose settings
JSON would be unchanged.

Also condenses the BulkAdjust doc comment back to the two-line maximum.

* docs(api): regenerate the bulkAdjust reference for limitHwid and adTag

frontend/public/openapi.json was copied to docs/public/, but pnpm gen:api
was never re-run, so the API reference page's heading, anchor id and search
index still described bulkAdjust without limitHwid or adTag. docs-ci.yml
fires only on docs/**, and that path had been touched, so nothing flagged
the stale MDX.

The externalLinks hunks are the generator rewrapping lines main had left
stale, not a content change.

* fix(i18n): stop enumerating fields in the bulk-adjust empty-form message

bulkAdjustNothing listed the fields the form accepts, so it went stale
every time one was added: only en-US ever gained "flow", leaving the other
twelve locales describing days and traffic alone, and limitHwid and adTag
would have repeated that. Say that one field is required instead of naming
which, so the message cannot drift again.

internal/web/translation/zh-CN.json

@@ -846,7 +846,7 @@
       "bulkDeleteConfirmContent": "每个所选客户端都会从关联的入站中被移除，其流量记录也会被删除。该操作不可撤销。",
       "bulkAdjustTitle": "调整 {count} 个客户端",
       "bulkAdjustHint": "正值延长，负值减少。具有无限期限或流量的客户端将跳过该字段。",
-      "bulkAdjustNothing": "应用前请设置天数或流量。",
+      "bulkAdjustNothing": "应用前请至少设置一项。",
       "addDays": "添加天数",
       "addTrafficGB": "添加流量 (GB)",
       "bulkFlow": "设置 flow",
@@ -912,7 +912,8 @@
       "renewMaxDesc": "自动续期最多可触发的次数，达到后客户端将自然到期。填 0 表示不限制。补齐多个错过的周期时，每个周期消耗一次续期。",
       "renewOnDay": "按日期续期",
       "renewOnDayDesc": "每个自然月的这一天午夜（按面板时区）续期，而不是每 N 天续期一次。若当月没有该日期，则在当月最后一天续期。填 0 保持按天间隔模式。",
-      "renewsUsed": "已用续期次数"
+      "renewsUsed": "已用续期次数",
+      "bulkAdTagHint": "输入 32 位十六进制标签以设置，或输入 'none' 清除 MTProto 赞助频道。"
     },
     "groups": {
       "name": "名称",