feat(inbounds): add multi-select and bulk delete

Mirror the clients page: checkbox selection on the desktop table and on
mobile cards, with a danger Delete button in the toolbar that removes all
selected inbounds in one call.

Backend adds POST /panel/api/inbounds/bulkDel, which loops the existing
DelInbound per id (xray restarts at most once) and returns {deleted,
skipped}. Frontend shows a confirm modal plus a result toast, clears the
selection on success, adds bulk-delete i18n keys across all 13 languages,
and documents the endpoint in the in-panel API docs.

web/translation/en-US.json

@@ -296,6 +296,10 @@
       "deleteConfirmContent": "This removes the inbound and all its clients. This cannot be undone.",
       "resetConfirmTitle": "Reset traffic for \"{remark}\"?",
       "resetConfirmContent": "Resets up/down counters to 0 for this inbound.",
+      "selectedCount": "{count} selected",
+      "selectAll": "Select all",
+      "bulkDeleteConfirmTitle": "Delete {count} inbounds?",
+      "bulkDeleteConfirmContent": "This removes the selected inbounds and all their clients. This cannot be undone.",
       "cloneConfirmTitle": "Clone inbound \"{remark}\"?",
       "cloneConfirmContent": "Creates a copy with a new port and an empty client list.",
       "delAllClients": "Delete All Clients",
@@ -421,6 +425,8 @@
         "inboundsUpdateSuccess": "Inbounds have been successfully updated.",
         "inboundUpdateSuccess": "Inbound has been successfully updated.",
         "inboundCreateSuccess": "Inbound has been successfully created.",
+        "bulkDeleted": "{count} inbounds deleted",
+        "bulkDeletedMixed": "{ok} deleted, {failed} failed",
         "inboundDeleteSuccess": "Inbound has been successfully deleted.",
         "inboundClientAddSuccess": "Inbound client(s) have been added.",
         "inboundClientDeleteSuccess": "Inbound client has been deleted.",