Add missing useEffect cleanup functions to prevent memory leaks

## Describe the bug
Some React components and hooks register side effects inside `useEffect` (such as event listeners, timers, or async operations) without returning cleanup functions.
This can lead to memory leaks or unexpected behavior when components unmount or when effects re-run due to dependency changes.

## To Reproduce
Steps to reproduce the behavior:

1. Navigate to pages that use the affected components (e.g. search or map-related views).
2. Interact with the page (search, navigation, map interactions).
3. Navigate away from the page or trigger re-renders.
4. Observe that side effects may remain active after unmount (e.g. duplicated listeners, stale state updates).

## Expected behavior
All `useEffect` hooks that register side effects should return appropriate cleanup functions so that resources are released correctly when components unmount or dependencies change.

## Are you going to work on fixing this?

- [x] Yes
- [ ] No

## Screenshots
Not applicable.

## Desktop (please complete the following information):
- OS: Any
- Browser: Any modern browser
- Version: N/A

## Smartphone (please complete the following information):
- Device: N/A
- OS: N/A
- Browser: N/A
- Version: N/A

## Additional context
Affected files include:
- `ChapterMap.tsx`
- `MultiSearch.tsx`
- `useSearchPage.ts`

Adding cleanup functions (e.g. removing event listeners, clearing timers, aborting async operations) will align these components with React best practices and prevent potential memory leaks.