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

docs/.vscode/extensions.json

@@ -0,0 +1,4 @@
+{
+	"recommendations": ["astro-build.astro-vscode"],
+	"unwantedRecommendations": []
+}