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

templates/starter-cloudflare/.gitignore

@@ -0,0 +1,12 @@
+node_modules
+dist
+.astro
+uploads
+data.db
+
+# Environment / Wrangler secrets
+.env
+.env.*
+!.env.example
+.dev.vars
+.dev.vars.*