fix: restore PDF pen capture and overhaul sticky/pens/pages

Reinstall PenCaptureBinding so stylus ink hits again; keep finger Listener translucent under pinch; page-anchor sticky with drag/resize; OneNote pen slots (brush+width+color); blank-note multi-page; default side button to hold-select-text.

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

lib/editor/persistence/sidecar_repository.dart

@@ -128,12 +128,38 @@ class SidecarRepository {
     }
     final file = File('$sourceFilePath$kSidecarSuffix');
     final loaded = await SidecarStore.read(file);
-    final sidecar = loaded ??
+    var sidecar = loaded ??
         BadnoteSidecar(
           sourceFile: _basename(sourceFilePath),
           docType: docType,
+          pageCount: docType == 'notebook' ? 1 : null,
           createdAt: DateTime.now().toUtc(),
         );
+    // Standalone notebooks always carry an explicit pageCount (min 1). Older
+    // sidecars that omit it are normalized in-memory on open.
+    if (docType == 'notebook' &&
+        (sidecar.pageCount == null || sidecar.pageCount! < 1)) {
+      sidecar = BadnoteSidecar(
+        version: sidecar.version,
+        sourceFile: sidecar.sourceFile,
+        docType: sidecar.docType,
+        title: sidecar.title,
+        pageCount: 1,
+        rotation: sidecar.rotation,
+        createdAt: sidecar.createdAt,
+        updatedAt: sidecar.updatedAt,
+        strokes: sidecar.strokes,
+        highlights: sidecar.highlights,
+        texts: sidecar.texts,
+        bookmarks: sidecar.bookmarks,
+        scratchLinks: sidecar.scratchLinks,
+        legacyAnnotations: sidecar.legacyAnnotations,
+        ocrText: sidecar.ocrText,
+        pageText: sidecar.pageText,
+        legacyId: sidecar.legacyId,
+        background: sidecar.background,
+      );
+    }
     final repo = SidecarRepository._(
       sourceFilePath: sourceFilePath,
       sidecar: sidecar,
@@ -220,6 +246,14 @@ class SidecarRepository {
     _replace(strokes: next);
   }
 
+  /// Replace the standalone-notebook page count and schedule a save. No-op if
+  /// unchanged. [count] is clamped to at least 1.
+  void schedulePageCountSave(int count) {
+    final next = count < 1 ? 1 : count;
+    if (_sidecar.pageCount == next) return;
+    _replace(pageCount: next);
+  }
+
   /// Replace the highlight rects for [pageIndex] and schedule a save.
   void scheduleHighlightSave(int pageIndex, List<SidecarHighlight> highlights) {
     final next = Map<int, List<SidecarHighlight>>.from(_sidecar.highlights);
@@ -345,6 +379,7 @@ class SidecarRepository {
   /// synchronously here so a later edit can't corrupt an in-flight write.
   void _replace({
     String? title,
+    int? pageCount,
     Map<int, List<EditorStroke>>? strokes,
     Map<int, List<SidecarHighlight>>? highlights,
     Map<int, List<SidecarText>>? texts,
@@ -362,7 +397,7 @@ class SidecarRepository {
       sourceFile: _sidecar.sourceFile,
       docType: _sidecar.docType,
       title: title ?? _sidecar.title,
-      pageCount: _sidecar.pageCount,
+      pageCount: pageCount ?? _sidecar.pageCount,
       rotation: _sidecar.rotation,
       createdAt: _sidecar.createdAt,
       updatedAt: DateTime.now().toUtc(),