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/core/vitest.integration.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+	test: {
+		globals: true,
+		environment: "node",
+		include: ["tests/integration/cli/**/*.test.ts", "tests/integration/client/**/*.test.ts"],
+		// These tests boot real Astro dev servers in beforeAll hooks.
+		// Default hookTimeout (10s) is too short -- server startup +
+		// migrations + seed can take 30-60s.
+		testTimeout: 30_000,
+		hookTimeout: 120_000,
+	},
+});