open as worspace implementation

src/components/HelpDialog.tsx

@@ -45,11 +45,15 @@ const tutorialSteps = [
     body: "Use the checkbox on a page card to select it. Shift-click extends a range. Dragging a selected page moves the whole selection; the copy controls duplicate selected pages into a chosen slot.",
   },
   {
-    title: "4. Save your workspace or export a PDF",
+    title: "4. Extract selected pages or branch into a new workspace",
+    body: "Extract selected pages when you only need a download. Open the selection as a new workspace when you want to continue working on that subset.",
+  },
+  {
+    title: "5. Save your workspace or export a PDF",
     body: "Saving a workspace keeps the current working state in this browser. Exporting creates a new PDF file for download.",
   },
   {
-    title: "5. Use history deliberately",
+    title: "6. Use history deliberately",
     body: "Each workspace operation is stored as a command with label and timestamp. Undo and redo walk through that command history.",
   },
 ];