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

packages/marketplace/vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+	test: {
+		globals: true,
+		include: ["tests/**/*.test.ts"],
+	},
+});