fix: close search modal on Escape key and backdrop click

fix: correct Configuration section icon slug

feat: add tooltips to sticky header icon buttons

feat: add tooltip to theme toggle button

feat: add dynamic tooltip to header view toggle button

feat: add custom tooltip styles for icon buttons

fix: listen for sheet-zoom-section event from search

fix: open zoom modal from search results in sheet mode

fix: hide mobile TOC button in sheet mode

fix: disconnect scroll spy observers in sheet mode

feat: add view mode toggle to sticky header

feat: add sheet mode toggle button and view switching logic

feat: add SheetMode component with card grid and zoom modal

feat: add FOUC prevention for sheet mode

feat: add sheet mode CSS styles and animations