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/ja-JP.json

@@ -846,7 +846,7 @@
       "bulkDeleteConfirmContent": "選択された各クライアントを関連付けされたすべてのインバウンドから削除し、トラフィック記録も破棄します。元に戻せません。",
       "bulkAdjustTitle": "{count} 件のクライアントを調整",
       "bulkAdjustHint": "正の値は延長、負の値は短縮します。無期限の有効期限または無制限のトラフィックを持つクライアントは、その項目についてスキップされます。",
-      "bulkAdjustNothing": "適用する前に日数またはトラフィックを設定してください。",
+      "bulkAdjustNothing": "適用する前に少なくとも1つの項目を設定してください。",
       "addDays": "日数を追加",
       "addTrafficGB": "トラフィックを追加 (GB)",
       "bulkFlow": "Flow を設定",
@@ -912,7 +912,8 @@
       "renewMaxDesc": "自動更新が実行される最大回数です。これを超えるとクライアントはそのまま失効します。0 は無制限。複数の未処理期間をまとめて処理する場合、1 期間につき 1 回消費します。",
       "renewOnDay": "更新する日",
       "renewOnDayDesc": "毎月この日の深夜（パネルのタイムゾーン基準）に更新します。N 日ごとの更新の代わりになります。その日が存在しない月は月末に更新されます。0 で日数間隔モードのままになります。",
-      "renewsUsed": "使用済み更新回数"
+      "renewsUsed": "使用済み更新回数",
+      "bulkAdTagHint": "設定するには 32 文字の 16 進数タグを入力し、クリアするには 'none' を入力します (MTProto 用)。"
     },
     "groups": {
       "name": "名前",