fix: remove custom font size from placeholders and hide embeds in previews

- Remove text-sm from MediaPlaceholder and EventPlaceholder to inherit parent font size
- Add options to hide media and event embeds in HighlightRenderer preview
- Ensures placeholders like [image], [note] match surrounding text size

src/components/nostr/RichText/Gallery.tsx

@@ -9,7 +9,7 @@ import { MediaEmbed } from "../MediaEmbed";
 import { useRichTextOptions } from "../RichText";
 
 function MediaPlaceholder({ type }: { type: "image" | "video" | "audio" }) {
-  return <span className="text-muted-foreground text-sm">[{type}]</span>;
+  return <span className="text-muted-foreground">[{type}]</span>;
 }
 
 interface GalleryNodeProps {

src/components/nostr/RichText/Mention.tsx

@@ -7,7 +7,7 @@ import { getKindName } from "@/constants/kinds";
 
 function EventPlaceholder({ kind }: { kind?: number }) {
   const name = kind !== undefined ? getKindName(kind) : "event";
-  return <span className="text-muted-foreground text-sm">[{name}]</span>;
+  return <span className="text-muted-foreground">[{name}]</span>;
 }
 
 interface MentionNodeProps {

src/components/nostr/kinds/HighlightRenderer.tsx

@@ -94,7 +94,10 @@ export function Kind9802Renderer({ event }: BaseEventProps) {
                 className="hover:underline hover:decoration-dotted cursor-crosshair text-xs line-clamp-1 break-words"
                 onClick={handleOpenEvent}
               >
-                <RichText content={sourcePreview} />
+                <RichText
+                  content={sourcePreview}
+                  options={{ showMedia: false, showEventEmbeds: false }}
+                />
               </div>
             )}
           </div>