feat: unified shell, diagnostics pack, native Office, sticky board

Make Surface remote debugging and classroom workflows viable: always-on
structured logs with one-click zip export, a single AppShell chrome,
OOXML PPTX/DOCX annotation without LibreOffice, and a first-class sticky
board. Also drop spike/legacy ink widgets and tighten pen feel
(predictor, PenInfoHistory, page-tile layer).

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

lib/screens/search_screen.dart

@@ -10,7 +10,9 @@ import '../providers/search_provider.dart';
 import '../editor/canvas/pen_note_screen.dart';
 
 class SearchScreen extends ConsumerStatefulWidget {
-  const SearchScreen({super.key});
+  const SearchScreen({super.key, this.embeddedInShell = false});
+
+  final bool embeddedInShell;
 
   @override
   ConsumerState<SearchScreen> createState() => _SearchScreenState();