Address RBAC review feedback

src/app/components/RoomMembers.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import {first, sortBy} from "@welshman/lib"
+  import {first, removeUndefined, sortBy} from "@welshman/lib"
   import {waitForThunkError, removeRoomMember} from "@welshman/app"
   import MenuDots from "@assets/icons/menu-dots.svg?dataurl"
   import MinusCircle from "@assets/icons/minus-circle.svg?dataurl"
@@ -21,8 +21,15 @@
   import RoomName from "@app/components/RoomName.svelte"
   import RoomMembersAdd from "@app/components/RoomMembersAdd.svelte"
   import type {RoomMember} from "@app/core/roles"
-  import {deriveRoom, deriveRoomMembers} from "@app/core/state"
-  import {deriveRoomRoles, hasPermission} from "@app/core/roles"
+  import {
+    deriveRoomMembers,
+    deriveRoomRoles,
+    deriveHasPermission,
+    sortRolesDesc,
+    ROOM_PERMISSION_ADD_MEMBER,
+    ROOM_PERMISSION_REMOVE_MEMBER,
+  } from "@app/core/roles"
+  import {deriveRoom} from "@app/core/state"
   import {pushModal} from "@app/util/modal"
   import {pushToast} from "@app/util/toast"
 
@@ -36,8 +43,8 @@
   const room = deriveRoom(url, h)
   const members = deriveRoomMembers(url, h)
   const roomRoles = deriveRoomRoles(url, h)
-  const canAddMembers = hasPermission(url, h, 9000)
-  const canRemoveMembers = hasPermission(url, h, 9001)
+  const canAddMembers = deriveHasPermission(url, h, ROOM_PERMISSION_ADD_MEMBER)
+  const canRemoveMembers = deriveHasPermission(url, h, ROOM_PERMISSION_REMOVE_MEMBER)
 
   const back = () => history.back()
 
@@ -52,8 +59,7 @@
   const getResolvedRoles = (member: RoomMember) =>
     removeUndefined(member.roles.map(roleName => $roomRoles.roles.get(roleName)))
 
-  const getPrimaryRole = (member: RoomMember) =>
-    first(sortBy(role => -(role.order ?? -Infinity), getResolvedRoles(member)))
+  const getPrimaryRole = (member: RoomMember) => first(sortRolesDesc(getResolvedRoles(member)))
 
   const memberGroups = $derived.by(() => {
     const byRole = new Map<
@@ -102,9 +108,6 @@
     return groups
   })
 
-  const removeUndefined = <T,>(items: Array<T | undefined>): T[] =>
-    items.filter((item): item is T => item !== undefined)
-
   const addMember = () => pushModal(RoomMembersAdd, {url, h})
 
   const removeMember = (pubkey: string) =>