Fix item pane section button icons in light and dark themes.

Wire stroke context properties for Lucide SVG toolbar icons and set light/dark icon URLs on open-in-window and adaptive-height buttons.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/modules/lecture/ui/registerLecturePane.ts

@@ -4,6 +4,7 @@ import { findPdfAttachment } from "../../pdf/extractor";
 import { ensureChatPapersStyles } from "../../ui/readerPane";
 import {
   applyAdaptiveHeight,
+  applyItemPaneSectionButtonIcons,
   buildItemPaneSectionButtons,
   onItemPaneSectionToggle,
   prepareItemPaneBody,
@@ -71,6 +72,7 @@ export function registerLecturePane() {
         body.append(err);
       }
       applyAdaptiveHeight(body, "lecture");
+      applyItemPaneSectionButtonIcons(body);
       const section = body.closest("collapsible-section");
       if (section?.hasAttribute("open")) {
         refreshSectionOpenHeight(body);