promote jsdom to a dependency

Author: mbostock

package.json

@@ -53,6 +53,7 @@
     "@sindresorhus/slugify": "^2.2.1",
     "acorn": "^8.15.0",
     "acorn-walk": "^8.3.4",
+    "jsdom": "^26.1.0",
     "markdown-it": "^14.1.0",
     "markdown-it-anchor": "^9.2.0",
     "vite": "^7.0.0"
@@ -64,7 +65,6 @@
     "eslint": "^9.29.0",
     "globals": "^16.2.0",
     "htl": "^0.3.1",
-    "jsdom": "^26.1.0",
     "tsx": "^4.20.3",
     "typescript": "^5.8.3",
     "typescript-eslint": "^8.35.0",