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.

tests/unit/notes.test.ts

@@ -2,7 +2,8 @@ import { describe, it, expect } from 'vitest';
 import { noteLabel, noteLabels, type NoteRefInfo } from '../../src/lib/editor/extensions/notes';
 import { clampNoteSettings, DEFAULT_NOTE_SETTINGS, type NoteSettings } from '../../src/lib/storage/noteSettings';
 
-const REF = (id: string, kind: 'footnote' | 'endnote'): NoteRefInfo => ({ id, kind, pos: 0 });
+const REF = (id: string, kind: 'footnote' | 'endnote', chapter = 0): NoteRefInfo =>
+  ({ id, kind, pos: 0, chapter });
 
 const withFootnote = (over: Partial<NoteSettings['footnote']>): NoteSettings =>
   ({ ...DEFAULT_NOTE_SETTINGS, footnote: { ...DEFAULT_NOTE_SETTINGS.footnote, ...over } });
@@ -38,6 +39,25 @@ describe('note numbering', () => {
     const labels = noteLabels(refs, DEFAULT_NOTE_SETTINGS);
     expect([...labels.values()]).toEqual(['1', 'i', '2', 'ii']);
   });
+
+  // LibreOffice, probed: the count starts over on each page / at each chapter.
+  it('restarts per page, from the page each anchor landed on', () => {
+    const refs = [REF('a', 'footnote'), REF('b', 'footnote'), REF('c', 'footnote')];
+    const pages = new Map([['a', 1], ['b', 2], ['c', 2]]);
+    const labels = noteLabels(refs, withFootnote({ restart: 'page' }), pages);
+    expect([...labels.values()]).toEqual(['1', '1', '2']);
+  });
+
+  it('leaves an endnote document-wide: LibreOffice offers no per-page count for one', () => {
+    const refs = [REF('a', 'endnote'), REF('b', 'endnote')];
+    const s: NoteSettings = { ...DEFAULT_NOTE_SETTINGS, endnote: { ...DEFAULT_NOTE_SETTINGS.endnote, restart: 'page' } };
+    expect([...noteLabels(refs, s, new Map()).values()]).toEqual(['i', 'ii']);
+  });
+
+  it('restarts per chapter, off the anchor’s own chapter', () => {
+    const refs = [REF('a', 'footnote', 1), REF('b', 'footnote', 1), REF('c', 'footnote', 2)];
+    expect([...noteLabels(refs, withFootnote({ restart: 'chapter' })).values()]).toEqual(['1', '2', '1']);
+  });
 });
 
 describe('note settings', () => {