Fix "continuous vertical pager" unintentional page gaps

Depending on the screen size and e.g. the set "reader width" pages might not have filled out the full img elements size due to "object-fit contain".
This was caused due to the image wrappers flex container "align-items center" which slightly reduced the images width to some ".xy" number (e.g. instead of wrappers width 258px, the images were something like 257.83px)

src/modules/reader/components/viewer/ReaderViewer.tsx

@@ -35,10 +35,14 @@ import { useReaderScrollbarContext } from '@/modules/reader/contexts/ReaderScrol
 import { MediaQuery } from '@/modules/core/utils/MediaQuery.tsx';
 import { ReaderControls } from '@/modules/reader/services/ReaderControls.ts';
 import { getNextIndexFromPage, getPage } from '@/modules/reader/utils/ReaderProgressBar.utils.tsx';
-import { isContinuousReadingMode } from '@/modules/reader/utils/ReaderSettings.utils.tsx';
+import {
+    isContinuousReadingMode,
+    isContinuousVerticalReadingMode,
+} from '@/modules/reader/utils/ReaderSettings.utils.tsx';
 import { useMouseDragScroll } from '@/modules/core/hooks/useMouseDragScroll.tsx';
 import { DirectionOffset } from '@/Base.types.ts';
 import { useReaderOverlayContext } from '@/modules/reader/contexts/ReaderOverlayContext.tsx';
+import { applyStyles } from '@/modules/core/utils/ApplyStyles.ts';
 
 const READING_MODE_TO_IN_VIEWPORT_TYPE: Record<ReadingMode, PageInViewportType> = {
     [ReadingMode.SINGLE_PAGE]: PageInViewportType.X,
@@ -244,7 +248,12 @@ export const ReaderViewer = forwardRef((_, ref: ForwardedRef<HTMLDivElement | nu
     return (
         <Stack
             ref={scrollElementRef}
-            sx={{ width: '100%', height: '100%', overflow: 'auto' }}
+            sx={{
+                width: '100%',
+                height: '100%',
+                overflow: 'auto',
+                ...applyStyles(isContinuousVerticalReadingMode(readingMode.value), { alignItems: 'center' }),
+            }}
             onClick={(e) => !isDragging && handleClick(e)}
             onScroll={() =>
                 ReaderControls.updateCurrentPageOnScroll(