fix: footnote counting per page/chapter and collecting at the end really work

Both were selectable in the dialog and changed nothing — they only rode the
file formats, so an imported document numbered and placed its notes wrong.
noteLabels now counts within a bucket (class, chapter, or the page pageBreaks
publishes through setNoteAnchorPages); a collected footnote leaves position:
absolute and opens its own page, as LibreOffice does. Counting and position
move to the footnote tab, the only place LibreOffice offers them.

The separator's own alignment moves the line alone — probed, notes stay left.

src/styles/editor.css

@@ -278,6 +278,11 @@
   left: var(--page-margin-left);
   right: var(--page-margin-right);
 }
+/* Collected at the end of the document instead (noteSettings.ts): the footnotes rejoin
+   the flow and open their own page, where the endnote list also starts. */
+:root[data-collect-footnotes] .paper .tiptap .note[data-note-kind='footnote'] {
+  position: static;
+}
 /* The separator hangs above the first note of a page, inside the band pageBreaks.ts
    already reserved for it — so it costs the note's own box no height, which is what
    keeps that height out of the reservation that produced it. A gradient, not a