fix(moderation): knock Deny gated on kick power; approve/deny errors surfaced

Fixes #49

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/room/MembersDrawer.tsx

@@ -30,6 +30,7 @@ import {
 import { MatrixClient, Room, RoomMember } from 'matrix-js-sdk';
 import { useVirtualizer } from '@tanstack/react-virtual';
 import classNames from 'classnames';
+import { useSetAtom } from 'jotai';
 import { MobileTouchTarget } from '../../styles/mobile.css';
 import { Membership } from '../../../types/matrix/room';
 
@@ -71,6 +72,7 @@ import { MemberVerificationBadge } from '../../components/MemberVerificationBadg
 import { useUserPresence } from '../../hooks/useUserPresence';
 import { PresenceBadge, PresenceRingAvatar } from '../../components/presence';
 import { AvatarDecoration } from '../../components/avatar-decoration/AvatarDecoration';
+import { createErrorToast, toastQueueAtom } from '../../state/toast';
 
 type MemberDrawerHeaderProps = {
   room: Room;
@@ -239,11 +241,55 @@ export function MembersDrawer({ room, members }: MembersDrawerProps) {
   const myUserId = mx.getUserId();
   const myPowerLevel = readPowerLevel.user(powerLevels, myUserId ?? undefined);
   const invitePowerLevel = readPowerLevel.action(powerLevels, 'invite');
+  const kickPowerLevel = readPowerLevel.action(powerLevels, 'kick');
   const canApproveKnock = myPowerLevel >= invitePowerLevel;
+  // Deny uses mx.kick, which is gated by the room's kick power level, not invite -
+  // these can differ (e.g. moderators can invite but only admins can kick).
+  const canDenyKnock = myPowerLevel >= kickPowerLevel;
   const knockMembers = useMemo(
     () => (canApproveKnock ? room.getMembersWithMembership(Membership.Knock) : []),
     [room, canApproveKnock],
   );
+  const setToast = useSetAtom(toastQueueAtom);
+  const [pendingKnockAction, setPendingKnockAction] = useState<string | undefined>(undefined);
+
+  const handleApproveKnock = useCallback(
+    (userId: string) => {
+      setPendingKnockAction(userId);
+      mx.invite(room.roomId, userId)
+        .catch((err: unknown) => {
+          console.error('Failed to approve knock request:', err);
+          setToast(
+            createErrorToast(
+              'Could not approve this request. Please try again.',
+              Icons.Warning,
+              'Failed',
+            ),
+          );
+        })
+        .finally(() => setPendingKnockAction(undefined));
+    },
+    [mx, room.roomId, setToast],
+  );
+
+  const handleDenyKnock = useCallback(
+    (userId: string) => {
+      setPendingKnockAction(userId);
+      mx.kick(room.roomId, userId)
+        .catch((err: unknown) => {
+          console.error('Failed to deny knock request:', err);
+          setToast(
+            createErrorToast(
+              'Could not deny this request. Please try again.',
+              Icons.Warning,
+              'Failed',
+            ),
+          );
+        })
+        .finally(() => setPendingKnockAction(undefined));
+    },
+    [mx, room.roomId, setToast],
+  );
 
   const filteredMembers = useMemo(
     () => members.filter(membershipFilter.filterFn).sort(memberSort.sortFn).sort(memberPowerSort),
@@ -462,20 +508,24 @@ export function MembersDrawer({ room, members }: MembersDrawerProps) {
                           radii="300"
                           fill="Soft"
                           className={MobileTouchTarget}
-                          onClick={() => mx.invite(room.roomId, knockMember.userId)}
+                          disabled={pendingKnockAction === knockMember.userId}
+                          onClick={() => handleApproveKnock(knockMember.userId)}
                         >
                           <Text size="B300">Approve</Text>
                         </Button>
-                        <Button
-                          size="300"
-                          variant="Critical"
-                          radii="300"
-                          fill="Soft"
-                          className={MobileTouchTarget}
-                          onClick={() => mx.kick(room.roomId, knockMember.userId)}
-                        >
-                          <Text size="B300">Deny</Text>
-                        </Button>
+                        {canDenyKnock && (
+                          <Button
+                            size="300"
+                            variant="Critical"
+                            radii="300"
+                            fill="Soft"
+                            className={MobileTouchTarget}
+                            disabled={pendingKnockAction === knockMember.userId}
+                            onClick={() => handleDenyKnock(knockMember.userId)}
+                          >
+                            <Text size="B300">Deny</Text>
+                          </Button>
+                        )}
                       </Box>
                     </Box>
                   );