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

demos/cloudflare/wrangler.jsonc

@@ -0,0 +1,41 @@
+{
+	"$schema": "node_modules/wrangler/config-schema.json",
+	"name": "emdash-demo",
+	"main": "./src/worker.ts",
+	"compatibility_date": "2026-01-14",
+	// disable_nodejs_process_v2 needed until unenv fix lands in Pages
+	// See: https://github.com/withastro/astro/issues/14511
+	"compatibility_flags": ["nodejs_compat", "disable_nodejs_process_v2"],
+	// Static assets served from dist/
+	"routes": [
+		{
+			"pattern": "demo.emdashcms.com",
+			"zone_name": "demo.emdashcms.com",
+			"custom_domain": true,
+		},
+	],
+	// D1 Database binding
+	"d1_databases": [
+		{
+			"binding": "DB",
+			"database_name": "emdash_db",
+		},
+	],
+	// R2 bucket for media storage
+	"r2_buckets": [
+		{
+			"binding": "MEDIA",
+			"bucket_name": "emdash-media",
+		},
+	],
+	// Observability
+	"observability": {
+		"enabled": true,
+	},
+	// Worker Loader for plugin sandboxing
+	"worker_loaders": [
+		{
+			"binding": "LOADER",
+		},
+	],
+}