fix(support): stop unnecessary assignable user fetching

client/src/components/support/BulkChangeModal.tsx

@@ -1,7 +1,7 @@
 import { useSupportCenterContext } from "../../context/SupportCenterContext";
 import useSupportQueues from "../../hooks/useSupportQueues";
-import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
-import { User } from "../../types";
+import useAssignableUsers from "../../hooks/useAssignableUsers";
+import { useMutation, useQueryClient } from "@tanstack/react-query";
 import api from "../../api";
 import { useForm } from "react-hook-form";
 import {
@@ -49,15 +49,7 @@ const BulkChangeModal: React.FC<BulkChangeModalProps> = ({
     withCount: false,
   });
 
-  const { data: assignableUsers } = useQuery<
-    Pick<User, "uuid" | "firstName" | "lastName" | "email" | "avatar">[]
-  >({
-    queryKey: ["assignableUsers"],
-    queryFn: async () => {
-      const res = await api.getSupportAssignableUsers();
-      return res.data.users;
-    },
-  });
+  const { data: assignableUsers } = useAssignableUsers({ enabled: open });
 
   useEffect(() => {
     if (open) {

client/src/components/support/QueueAutoAssignmentModal.tsx

@@ -11,7 +11,8 @@ import { IconCheck, IconX } from "@tabler/icons-react";
 import api from "../../api";
 import { useNotifications } from "../../context/NotificationContext";
 import { useSupportCenterContext } from "../../context/SupportCenterContext";
-import { SupportQueueAutoAssignConfig, User } from "../../types";
+import useAssignableUsers from "../../hooks/useAssignableUsers";
+import { SupportQueueAutoAssignConfig } from "../../types";
 
 interface QueueAutoAssignmentModalProps {
   open: boolean;
@@ -39,16 +40,8 @@ const QueueAutoAssignmentModal: React.FC<QueueAutoAssignmentModalProps> = ({
     enabled: open,
   });
 
-  const { data: assignableUsers, isLoading: isAssignableUsersLoading } = useQuery<
-    Pick<User, "uuid" | "firstName" | "lastName" | "email" | "avatar">[]
-  >({
-    queryKey: ["assignableUsers"],
-    queryFn: async () => {
-      const res = await api.getSupportAssignableUsers();
-      return res.data.users;
-    },
-    enabled: open,
-  });
+  const { data: assignableUsers, isLoading: isAssignableUsersLoading } =
+    useAssignableUsers({ enabled: open });
 
   // Default the selected queue to the one active in the sidebar, falling back to the first.
   useEffect(() => {

client/src/components/support/TicketAssigneePicker.tsx

@@ -1,13 +1,16 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from "react";
-import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useMutation, useQueryClient } from "@tanstack/react-query";
 import { Popover, PopoverButton, PopoverPanel } from "@headlessui/react";
 import { Avatar, Button, Input, Text } from "@libretexts/davis-react";
 import { IconCheck, IconPlus, IconSearch, IconX } from "@tabler/icons-react";
 import api from "../../api";
-import { User } from "../../types";
+import { SupportTicket } from "../../types";
 import { useNotifications } from "../../context/NotificationContext";
 import { useTypedSelector } from "../../state/hooks";
 import useDebounce from "../../hooks/useDebounce";
+import useAssignableUsers, {
+  AssignableUser,
+} from "../../hooks/useAssignableUsers";
 
 interface TicketAssigneePickerProps {
   ticketId: string;
@@ -23,11 +26,6 @@ interface TicketAssigneePickerProps {
   triggerId?: string;
 }
 
-type AssignableUser = Pick<
-  User,
-  "uuid" | "firstName" | "lastName" | "email" | "avatar"
->;
-
 const fullName = (u: AssignableUser) => `${u.firstName} ${u.lastName}`;
 
 const TicketAssigneePicker: React.FC<TicketAssigneePickerProps> = ({
@@ -50,12 +48,7 @@ const TicketAssigneePicker: React.FC<TicketAssigneePickerProps> = ({
     setSelected(assignedUUIDs ?? []);
   }, [assignedUUIDs]);
 
-  const { data: assignableUsers } = useQuery<AssignableUser[]>({
-    queryKey: ["assignableUsers"],
-    queryFn: async () => {
-      const res = await api.getSupportAssignableUsers();
-      return res.data.users;
-    },
+  const { data: assignableUsers } = useAssignableUsers({
     enabled: !!ticketId && !disabled,
   });
 
@@ -67,8 +60,31 @@ const TicketAssigneePicker: React.FC<TicketAssigneePickerProps> = ({
         throw new Error(res.data.errMsg);
       }
     },
-    onSuccess: async () => {
-      await queryClient.invalidateQueries(["ticket", ticketId]);
+    onSuccess: (_data, assignees) => {
+      // Patch the cached ticket so the UI settles immediately; the background
+      // invalidation below reconciles with the server without blocking the user.
+      // Additions resolve against the cached staff roster (falling back to the
+      // records already on the ticket) so both chips and any assignedUsers-driven
+      // UI stay correct even if the refetch is slow or fails.
+      queryClient.setQueryData<SupportTicket | undefined>(
+        ["ticket", ticketId],
+        (prev) => {
+          if (!prev) return prev;
+          const roster = assignableUsers ?? [];
+          return {
+            ...prev,
+            assignedUUIDs: assignees,
+            assignedUsers: assignees
+              .map(
+                (uuid) =>
+                  prev.assignedUsers?.find((u) => u.uuid === uuid) ??
+                  roster.find((u) => u.uuid === uuid)
+              )
+              .filter((u): u is AssignableUser => !!u),
+          };
+        }
+      );
+      queryClient.invalidateQueries(["ticket", ticketId]);
       addNotification({
         type: "success",
         message: "Successfully updated assignees.",
@@ -92,7 +108,7 @@ const TicketAssigneePicker: React.FC<TicketAssigneePickerProps> = ({
   mutateRef.current = updateAssignedMutation.mutate;
 
   const debouncedSave = useMemo(
-    () => debounce((assignees: string[]) => mutateRef.current(assignees), 500),
+    () => debounce((assignees: string[]) => mutateRef.current(assignees), 250),
     []
   );
 

client/src/hooks/useAssignableUsers.ts

@@ -0,0 +1,42 @@
+import { useQuery, useQueryClient } from "@tanstack/react-query";
+import { AssignableUser } from "../types";
+import api from "../api";
+
+export type { AssignableUser };
+
+/**
+ * Shared access to the support staff roster. The roster is small and near-static,
+ * so it is cached aggressively — every surface that offers assignment (ticket
+ * picker, bulk change, queue auto-assignment) reads the same cache entry instead
+ * of issuing its own request.
+ */
+const useAssignableUsers = ({ enabled = true }: { enabled?: boolean } = {}) => {
+    const QUERY_KEY = ['assignableUsers'];
+    const queryClient = useQueryClient();
+
+    const queryObj = useQuery<AssignableUser[]>({
+        queryKey: QUERY_KEY,
+        queryFn: async () => {
+            const res = await api.getSupportAssignableUsers();
+            if (res.data.err) {
+                throw new Error(res.data.errMsg);
+            }
+            return res.data.users;
+        },
+        enabled,
+        staleTime: 5 * 60 * 1000, // 5 minutes
+        cacheTime: 30 * 60 * 1000, // survives navigation between the dashboard and a ticket
+        refetchOnWindowFocus: false,
+        meta: {
+            errorMessage: "Failed to fetch assignable users.",
+        }
+    })
+
+    const invalidate = () => {
+        return queryClient.invalidateQueries({ queryKey: QUERY_KEY });
+    }
+
+    return { ...queryObj, QUERY_KEY, invalidate };
+}
+
+export default useAssignableUsers

client/src/screens/conductor/support/Ticket.tsx

@@ -23,6 +23,7 @@ import { useDocumentTitle } from "usehooks-ts";
 import AuthHelper from "../../../components/util/AuthHelper";
 import { Button, Heading, Stack } from "@libretexts/davis-react";
 import { IconCheck, IconRefresh, IconTrash } from "@tabler/icons-react";
+import useAssignableUsers from "../../../hooks/useAssignableUsers";
 
 const getIdFromURL = (url: string) => {
   if (!url) return "";
@@ -62,6 +63,12 @@ const SupportTicketView = () => {
     enabled: !!id,
   });
 
+  // Warm the staff roster cache while the ticket loads so the assignee picker
+  // has data on hand the first time it is opened.
+  useAssignableUsers({
+    enabled: !!id && !!(user.isSupport || user.isHarvester),
+  });
+
   const updateTicketStatusMutation = useMutation({
     mutationFn: (status: "open" | "in_progress" | "closed") =>
       updateTicket({ status }),

client/src/types/User.ts

@@ -52,6 +52,16 @@ export type AuthorizedApp = {
   icon: string;
 };
 
+/**
+ * The narrow projection of a user returned by the support staff roster
+ * (`/support/assignable-users`). Assignment surfaces only ever need identity
+ * and avatar, so this is the shape they share.
+ */
+export type AssignableUser = Pick<
+  User,
+  "uuid" | "firstName" | "lastName" | "email" | "avatar"
+>;
+
 export type UserWCentralID = User & {
   centralID?: string;
 };

client/src/types/support.ts

@@ -1,5 +1,5 @@
 import { SupportQueue } from "./supportqueues";
-import { User, UserWCentralID } from "./User";
+import { AssignableUser, User, UserWCentralID } from "./User";
 
 export type SupportTicketGuest = {
   firstName: string;
@@ -30,7 +30,7 @@ export type SupportTicket = {
   category?: string;
   capturedURL?: string;
   assignedUUIDs?: string[]; // User uuids
-  assignedUsers?: UserWCentralID[];
+  assignedUsers?: AssignableUser[];
   user?: UserWCentralID;
   guest?: SupportTicketGuest;
   ccedEmails?: {

server/api/support.ts

@@ -459,7 +459,8 @@ async function _getAssignableUsersInternal(): Promise<Pick<UserInterface, "uuid"
       ],
     })
       .select("uuid firstName lastName email avatar")
-      .sort({ firstName: 1 });
+      .sort({ firstName: 1 })
+      .lean();
 
     return users;
   } catch (err) {