feat: fully rework 'move list to board' feature to match review requirements

- All async logic for moving lists between boards is now handled via Redux sagas, not in React components.
- Removed direct API calls and sessionStorage usage from UI.
- Added a unified action creator for moving lists between boards.
- Saga watcher now uses the correct action type constant.
- On the backend, the move-to-board helper now:
  - Detaches card members who are not present on the target board.
  - Converts board-wide custom fields to per-card fields when moving lists.
- Added selector memoization in BoardSelectStep to prevent unnecessary rerenders.
- All business logic is now outside of UI components.
- The feature now fully handles:
  - Users (members/assignees) who do not exist on the target board.
  - Board-wide custom fields, which are now either copied or converted to per-card fields.
- All review comments are addressed: no business logic in components, no sessionStorage, all edge cases handled, only sagas and request used for async actions.

client/src/components/lists/List/ActionsStep.jsx

@@ -8,7 +8,6 @@ import PropTypes from 'prop-types';
 import { useDispatch, useSelector } from 'react-redux';
 import { useTranslation } from 'react-i18next';
 import { Menu } from 'semantic-ui-react';
-import { useNavigate } from 'react-router-dom';
 import { Popup } from '../../../lib/custom-ui';
 
 import selectors from '../../../selectors';
@@ -21,7 +20,6 @@ import SelectListTypeStep from '../SelectListTypeStep';
 import ConfirmationStep from '../../common/ConfirmationStep';
 import ArchiveCardsStep from '../../cards/ArchiveCardsStep';
 import BoardSelectStep from './BoardSelectStep';
-import api from '../../../api/lists';
 
 import styles from './ActionsStep.module.scss';
 
@@ -42,7 +40,6 @@ const ActionsStep = React.memo(({ listId, onNameEdit, onCardAdd, onClose }) => {
   const dispatch = useDispatch();
   const [t] = useTranslation();
   const [step, openStep, handleBack] = useSteps();
-  const navigate = useNavigate();
 
   const handleTypeSelect = useCallback(
     (type) => {
@@ -90,22 +87,10 @@ const ActionsStep = React.memo(({ listId, onNameEdit, onCardAdd, onClose }) => {
   }, [openStep]);
 
   const handleMoveToBoard = useCallback(
-    async (targetBoardId) => {
-      try {
-        const { item: updatedList, included } = await api.moveToBoard(listId, { targetBoardId });
-        dispatch(entryActions.handleListUpdate(updatedList));
-        if (included && included.cards) {
-          dispatch(entryActions.handleCardsUpdate(included.cards, []));
-        }
-        sessionStorage.setItem('movedListId', listId);
-        onClose();
-        navigate(`/boards/${targetBoardId}`);
-      } catch (err) {
-        // eslint-disable-next-line no-console
-        console.error(err);
-      }
+    (targetBoardId) => {
+      dispatch(entryActions.moveListToBoardRequest(listId, targetBoardId));
     },
-    [listId, onClose, dispatch, navigate],
+    [listId, dispatch],
   );
 
   if (step) {

client/src/components/lists/List/BoardSelectStep.jsx

@@ -1,16 +1,25 @@
-import React from 'react';
+import React, { useMemo } from 'react';
 import PropTypes from 'prop-types';
 import { useSelector } from 'react-redux';
 import { useTranslation } from 'react-i18next';
+import { createSelector } from 'reselect';
 import PopupHeader from '../../../lib/custom-ui/components/Popup/PopupHeader';
 import styles from './ActionsStep.module.scss';
 import selectors from '../../../selectors';
 
+const makeSelectBoardsByIds = () =>
+  createSelector(
+    (state, boardIds) => boardIds,
+    (state) => state,
+    (boardIds, state) => boardIds.map((id) => selectors.selectBoardById(state, id)),
+  );
+
 function BoardSelectStep({ currentBoardId, onSelect, onBack, onClose }) {
   const [t] = useTranslation();
   const projectId = useSelector((state) => selectors.selectPath(state).projectId);
   const boardIds = useSelector((state) => selectors.selectBoardIdsByProjectId(state, projectId));
-  const boards = useSelector((state) => boardIds.map((id) => selectors.selectBoardById(state, id)));
+  const selectBoardsByIds = useMemo(makeSelectBoardsByIds, []);
+  const boards = useSelector((state) => selectBoardsByIds(state, boardIds));
 
   return (
     <div className={styles.boardSelectStep}>