fix(mobile): apply useModalStyle to 7 more modal dialogs

ScheduleMessageModal, PollCreator, JoinAddressPrompt, JumpToTime,
EditHistoryModal, ForwardMessageDialog, RemindMeDialog — all now
render fullscreen on mobile (≤750px) and as a capped-width box on
desktop, consistent with the existing useModalStyle pattern.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/components/join-address-prompt/JoinAddressPrompt.tsx

@@ -18,6 +18,7 @@ import {
 } from 'folds';
 import { stopPropagation } from '../../utils/keyboard';
 import { isRoomAlias, isRoomId } from '../../utils/matrix';
+import { useModalStyle } from '../../hooks/useModalStyle';
 import { parseMatrixToRoom, parseMatrixToRoomEvent, testMatrixTo } from '../../plugins/matrix-to';
 import { tryDecodeURIComponent } from '../../utils/dom';
 
@@ -26,6 +27,7 @@ type JoinAddressProps = {
   onCancel: () => void;
 };
 export function JoinAddressPrompt({ onOpen, onCancel }: JoinAddressProps) {
+  const modalStyle = useModalStyle(480);
   const [invalid, setInvalid] = useState(false);
 
   const handleSubmit: FormEventHandler<HTMLFormElement> = (evt) => {
@@ -71,7 +73,7 @@ export function JoinAddressPrompt({ onOpen, onCancel }: JoinAddressProps) {
             escapeDeactivates: stopPropagation,
           }}
         >
-          <Dialog variant="Surface">
+          <Dialog variant="Surface" style={modalStyle}>
             <Header
               style={{
                 padding: `0 ${config.space.S200} 0 ${config.space.S400}`,