chore(deps): update dependency vitest to v4

Author: renovate[bot]

package.json

@@ -10,7 +10,7 @@
     "publint": "0.3.16",
     "typescript": "5.9.3",
     "ultracite": "5.2.17",
-    "vitest": "3.2.4"
+    "vitest": "4.0.17"
   },
   "scripts": {
     "test": "moon run :build && vitest",

packages/runtime/package.json

@@ -30,7 +30,7 @@
     "type-fest": "5.4.0",
     "typescript": "5.9.3",
     "unbuild": "3.6.1",
-    "vitest": "3.2.4"
+    "vitest": "4.0.17"
   },
   "keywords": [
     "typespec",

packages/typespec/package.json

@@ -51,7 +51,7 @@
     "proper-tags": "2.0.2",
     "typescript": "5.9.3",
     "unbuild": "3.6.1",
-    "vitest": "3.2.4",
+    "vitest": "4.0.17",
     "zx": "8.8.5"
   },
   "scripts": {