fix(ui): native inputs/checkboxes, QR fallback, focus + report modal cleanup

- N23 RoomServerACL: raw text input -> folds Input; raw checkbox -> folds Checkbox
- N24 PolicyListViewer: raw room-id input -> folds Input (Critical variant on error)
- N25 ExportRoomHistory: raw <input type="date"> x2 -> folds Input
- N26 RoomShareInvite: QR <img> gets loading="lazy" + onError fallback card
  ("QR code unavailable") instead of a broken-image icon
- N27 GifPicker: FocusTrap returnFocusOnDeactivate:false (matches EmojiBoard)
- N76 Report modals: drop redundant Cancel button (dismiss via header x /
  click-outside, like MessageReportItem)
- N5 ReadReceiptAvatars: hover/focus moved to co-located css :hover/:focus-visible
  (removed JS onMouseEnter/Leave .style mutation)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/features/room/ReportUserModal.tsx

@@ -192,9 +192,6 @@ export function ReportUserModal({ userId, onClose }: ReportUserModalProps) {
               </Box>
 
               <Box gap="200" justifyContent="End">
-                <Button type="button" variant="Secondary" fill="None" radii="300" onClick={onClose}>
-                  <Text size="B400">Cancel</Text>
-                </Button>
                 <Button
                   type="submit"
                   variant="Critical"