Fix consecutive <br> collapsing into a single line break

src/main/java/org/jabref/htmltonode/rich/RichTextRenderer.java

@@ -166,8 +166,14 @@ private void paragraph(List<Inline> inlines, double scale, int minWeight, double
                     }
                     appendRun(text, effective);
                 }
-                case Inline.LineBreak ignored ->
-                        startParagraph(0);
+                case Inline.LineBreak ignored -> {
+                    // A break renders as a blank line even with no content of its own, so a second
+                    // consecutive break (e.g. `<br><br>`) still triggers a fresh model.nl() in the next
+                    // startParagraph() call instead of being swallowed by separateParagraph()'s
+                    // occupied-check (mirrors the empty-line handling for preserved "\n\n" in appendRun).
+                    startParagraph(0);
+                    paragraphOccupied = true;
+                }
                 case Inline.Image image -> {
                     if (RenderSupport.createImageView(image, options, baseSize) != null) {
                         model.addNodeSegment(() -> RenderSupport.createImageView(image, options, baseSize));

src/test/java/org/jabref/htmltonode/RichTextRendererTest.java

@@ -81,6 +81,16 @@ void lineBreaksSplitParagraphs() {
         assertEquals("b", model.getPlainText(1));
     }
 
+    @Test
+    void consecutiveLineBreaksKeepTheBlankLineBetweenThem() {
+        StyledTextModel model = model("a<br><br>b");
+
+        assertEquals(3, model.size());
+        assertEquals("a", model.getPlainText(0));
+        assertEquals("", model.getPlainText(1));
+        assertEquals("b", model.getPlainText(2));
+    }
+
     @Test
     void preservedNewlinesInPreSplitParagraphs() {
         StyledTextModel model = model("<pre>x = 1\ny = 2</pre>");