remove headers from page breaks

Thesis/style.typ

@@ -92,7 +92,18 @@
       let chapter-locs = query(heading.where(level: 1))
       let is-chapter-page = chapter-locs.any(h => counter(page).at(h.location()).first() == pg)
 
-      if chapter-locs.len() == 0 {} else if not is-chapter-page {
+      // Detect blank pages inserted by pagebreak(to: "odd").
+      // The marker is placed before the pagebreak, so it lands on the last page
+      // of the previous chapter (pg - 1 relative to the blank even page).
+      let chapter-break-markers = query(<chapter-break-marker>)
+      let is-blank-page = (
+        not is-odd
+          and chapter-break-markers.any(
+            m => counter(page).at(m.location()).first() == pg - 1,
+          )
+      )
+
+      if chapter-locs.len() == 0 {} else if not is-chapter-page and not is-blank-page {
         // Tytuł bieżącego rozdziału do nagłówka
         let prev = query(heading.where(level: 1).before(here()))
         let ch-label = if prev.len() > 0 {
@@ -174,6 +185,9 @@
 
     if it.level == 1 {
       // Wymuszenie nowej strony dla głównego rozdziału
+      // Marker placed before the break so it appears on the last page of the
+      // previous chapter; used by the header to detect blank even pages.
+      [#metadata("chapter-break") <chapter-break-marker>]
       pagebreak(to: "odd", weak: true)
       v(1.5em, weak: true)