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/es-ES.json

@@ -846,7 +846,7 @@
       "bulkDeleteConfirmContent": "Cada cliente seleccionado se elimina de los inbounds asociados y se descarta su registro de tráfico. No se puede deshacer.",
       "bulkAdjustTitle": "Ajustar {count} clientes",
       "bulkAdjustHint": "Los valores positivos extienden, los negativos reducen. Los clientes con expiración o tráfico ilimitado se omiten para ese campo.",
-      "bulkAdjustNothing": "Establece días o tráfico antes de aplicar.",
+      "bulkAdjustNothing": "Establece al menos un campo antes de aplicar.",
       "addDays": "Añadir días",
       "addTrafficGB": "Añadir tráfico (GB)",
       "bulkFlow": "Establecer flow",
@@ -912,7 +912,8 @@
       "renewMaxDesc": "Cuántas veces puede activarse la renovación automática antes de dejar que el cliente caduque. 0 significa sin límite. Recuperar varios periodos perdidos consume una renovación por periodo.",
       "renewOnDay": "Renovar el día",
       "renewOnDayDesc": "Renueva este día de cada mes natural, a medianoche en la zona horaria del panel, en lugar de cada N días. Si el mes es demasiado corto para el día elegido, renueva su último día. 0 mantiene el modo de intervalo en días.",
-      "renewsUsed": "Renovaciones usadas"
+      "renewsUsed": "Renovaciones usadas",
+      "bulkAdTagHint": "Introduce una etiqueta hexadecimal de 32 caracteres para asignar, o 'none' para borrarla en MTProto."
     },
     "groups": {
       "name": "Nombre",