FX.13 MarkupCraft: removed markups stayed readable inside the saved PDF

Found while building NOTES.1. Saving took a deleted or rewritten annotation off its page but left the object in the file, with its text and appearance, so anyone reading the PDF's bytes could still recover it. Save now deletes those objects, their appearance streams and photo attachments. Checked by opening every object and stream of saved files in bin/test-markupcraft-notes.mjs and tools/markupcraft-test/browser-notes.mjs. In /lab, not released. Copies saved by earlier builds still hold them until saved again.