fix: separate raised citation markers with a space, not a comma (#23)

src/lib/citations.ts

@@ -228,9 +228,11 @@ export function linkCitations(text: string, sources: Source[]): CitationResult {
       }
 
       for (const index of wanted) cited.add(index);
-      // Separated even when the model wrote them touching: `¹, ²` is two citations,
+      // Separated even when the model wrote them touching: `¹ ²` is two citations,
       // where `¹²` is a number, and the reader has no way to tell it from a real one.
-      return links.join(", ");
+      // A space rather than a comma, which sits at the baseline and so drops away from
+      // digits that are raised above it.
+      return links.join(" ");
     }),
   );