feat/enh: embed citation

src/lib/stores/index.ts

@@ -75,10 +75,12 @@ export const showArchivedChats = writable(false);
 export const showChangelog = writable(false);
 
 export const showControls = writable(false);
+export const showEmbeds = writable(false);
 export const showOverview = writable(false);
 export const showArtifacts = writable(false);
 export const showCallOverlay = writable(false);
 
+export const embed = writable(null);
 export const artifactCode = writable(null);
 
 export const temporaryChatEnabled = writable(false);