fix: drop the trailing-break line after an inline atom

A paragraph holding an image rendered a line taller than it does anywhere
else: under white-space: pre-wrap the browser already shows the last line, so
ProseMirror's hack BR adds an empty one. The hack is kept where it earns its
keep — after a real break it carries the caret onto the empty line, and in an
empty block it is the only line box there is.

src/styles/editor.css

@@ -623,6 +623,13 @@
   color: var(--color-primary);
 }
 
+/* After an inline atom ProseMirror's trailing-break BR adds a line the block has not
+   got, so a paragraph holding an image renders one too tall. Kept after a real BR
+   (it carries the caret onto the empty line) and in an empty block (its only line). */
+.paper .tiptap :not(br) + br.ProseMirror-trailingBreak {
+  display: none;
+}
+
 /* Empty block fix: a paragraph/heading/li-paragraph holding only the ProseMirror
    trailing-break BR would render the inline ¶ on a second line, doubling its height.
    Pull ::after out of flow. Applied always so the reserved ¶ stays zero-height. */