fix(web): limit protocol managers to active region leaders

Provide tenant-scoped leader options for the Web protocol form, exclude ordinary members and retain historical names only for display. Default only to a leader of the selected region and prevent delayed requests from replacing manual choices.

Refs #1. Add backend option isolation and Web cascade regression coverage.

web-admin/src/api/collection-protocol.ts

@@ -27,6 +27,14 @@ export function fetchCollectionProtocolList(params?: {
   })
 }
 
+export type ProtocolRegionManager = { id: string; nickName: string; regionIds: string[] }
+
+export function fetchProtocolRegionManagers() {
+  return request.get<{ list: ProtocolRegionManager[] }>({
+    url: '/web/admin/collection-protocols/region-managers'
+  })
+}
+
 export function fetchCollectionProtocolDetail(id: string) {
   return request.get<{
     protocol: Record<string, unknown>