R6.7: ElyMark keeps a single line break on screen

Component 93efa7f draws soft breaks as lines (Typora's default when
writing); exports and copies read with MarkdownReader::joined, as GFM.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/ely-mark/src/output/html.rs

@@ -28,7 +28,7 @@ pub(super) fn write(
         placed,
         page,
         source,
-        reader: MarkdownReader::new(source, tree),
+        reader: MarkdownReader::joined(source, tree),
         anchored: HashSet::new(),
     };
     writer.root(tree)

apps/ely-mark/src/output/plain.rs

@@ -11,7 +11,7 @@ use markdown::mdast::Node;
 pub fn plain(text: &str) -> io::Result<String> {
     let tree = markdown::to_mdast(text, &markdown_options())
         .map_err(|error| io::Error::other(error.to_string()))?;
-    let reader = MarkdownReader::new(text, &tree);
+    let reader = MarkdownReader::joined(text, &tree);
     let mut blocks = Vec::new();
     // Alerts and `[toc]` live only at the root.
     for child in tree.children().into_iter().flatten() {

apps/ely-mark/src/output/tests/visual.rs

@@ -230,3 +230,10 @@ fn a_copied_fragment_carries_its_look() {
         "the look needs no page style: {page}"
     );
 }
+
+#[test]
+fn a_soft_break_joins_in_exports_as_typora_exports_it() {
+    let page = html("你好\n测试  \nend\n");
+    assert!(page.contains("<p>你好 测试<br>end</p>"), "{page}");
+    assert_eq!(text("你好\n测试\n"), "你好 测试\n");
+}