Emdash source with visual editor image upload fix

Fixes:
1. media.ts: wrap placeholder generation in try-catch
2. toolbar.ts: check r.ok, display error message in popover

infra/blog-demo/src/utils/site-identity.ts

@@ -0,0 +1,24 @@
+/** Resolved media reference from getSiteSettings() */
+export interface MediaReference {
+	mediaId: string;
+	alt?: string;
+	url?: string;
+}
+
+export interface BlogSiteIdentitySettings {
+	title?: string;
+	tagline?: string;
+	logo?: MediaReference;
+	favicon?: MediaReference;
+}
+
+const DEFAULT_SITE_TITLE = "My Blog";
+const DEFAULT_SITE_TAGLINE = "Thoughts, stories, and ideas.";
+
+export function resolveBlogSiteIdentity(settings?: BlogSiteIdentitySettings) {
+	return {
+		siteTitle: settings?.title ?? DEFAULT_SITE_TITLE,
+		siteTagline: settings?.tagline ?? DEFAULT_SITE_TAGLINE,
+		siteLogo: settings?.logo?.url ? settings.logo : null,
+	};
+}