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/blocks/tsconfig.json

@@ -0,0 +1,11 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"compilerOptions": {
+		"outDir": "dist",
+		"rootDir": "src",
+		"jsx": "react-jsx",
+		"lib": ["ES2023", "DOM", "DOM.Iterable"]
+	},
+	"include": ["src/**/*"],
+	"exclude": ["node_modules", "dist", "tests"]
+}