fix: null safety in conversation monitor page

Prevent "Cannot read properties of null (reading forEach)" when
fetchTagsAll / fetchAgentProfilesAll / fetchAgentTeamsAll return null
from the API. Add null guard in buildTagOptions and array checks for
assignee/team data before calling .map.

web/app/dashboard/conversation-monitor/page.tsx

@@ -107,10 +107,11 @@ function getStatusLabel(value: string) {
 }
 
 function buildTagOptions(
-  nodes: TagTree[],
+  nodes: TagTree[] | null,
   parentPath = ""
 ): ComboboxOption[] {
   const result: ComboboxOption[] = []
+  if (!nodes) return result
   nodes.forEach((item) => {
     const currentPath = parentPath ? `${parentPath}/${item.name}` : item.name
     result.push({
@@ -207,18 +208,18 @@ export default function DashboardConversationsPage() {
         if (!cancelled) {
           setTagOptions([
             { value: "0", label: "全部标签" },
-            ...buildTagOptions(tagData),
+            ...buildTagOptions(tagData || []),
           ])
           setAssigneeOptions([
             { value: "0", label: "全部指派人" },
-            ...assigneeData.map((item: AdminAgentProfile) => ({
+            ...(Array.isArray(assigneeData) ? assigneeData : []).map((item: AdminAgentProfile) => ({
               value: String(item.userId),
               label: item.displayName || item.nickname || item.username || `#${item.userId}`,
             })),
           ])
           setAgentTeamOptions([
             { value: "0", label: "全部客服组" },
-            ...teamData.map((item: AdminAgentTeam) => ({
+            ...(Array.isArray(teamData) ? teamData : []).map((item: AdminAgentTeam) => ({
               value: String(item.id),
               label: item.name,
             })),