✨(frontend) make summary button fixed to remain visible during scroll

ensures persistent access to table of contents by fixing button position

Signed-off-by: Cyril <c.gromoff@gmail.com>

src/frontend/apps/impress/src/features/docs/doc-editor/components/DocEditor.tsx

@@ -99,6 +99,7 @@ export const DocEditor = ({ doc }: DocEditorProps) => {
     <>
       {isDesktop && (
         <Box
+          $height="100vh"
           $position="absolute"
           $css={css`
             top: 72px;

src/frontend/apps/impress/src/features/docs/doc-table-content/components/TableContent.tsx

@@ -108,9 +108,10 @@ export const TableContent = () => {
       $align="center"
       $padding={isHover ? 'xs' : '0'}
       $justify="center"
-      $position="relative"
+      $position="sticky"
       aria-label={t('Summary')}
       $css={css`
+        top: 0;
         border: 1px solid ${colorsTokens['greyscale-300']};
         overflow: hidden;
         border-radius: ${spacingsTokens['3xs']};