fix: TOC navigation and pagination improvements

- Fix recalculate_pages missing heading_top_spacing in page height calculation
- Improve build_toc path matching: extract filename first, fall back to substring
- Filter out EPUB3 nav.xhtml from content sections
- Skip Windows resource compilation when windres is not available
- Add unit tests for TOC filename matching and nav filtering

src/reader.rs

@@ -151,7 +151,11 @@ pub fn recalculate_pages(
             let block_height = measure_block_height(ctx, &display_text, block_font_size, available_width);
 
             let spacing = if i > page_start_block && i > 0 {
-                para_spacing
+                if block.heading_level > 0 {
+                    para_spacing + heading_top_spacing(para_spacing, block.heading_level)
+                } else {
+                    para_spacing
+                }
             } else {
                 0.0
             };