chore(deps): update dependency tsdown to v0.16.8

Author: renovate[bot]

package.json

@@ -72,7 +72,7 @@
     "dotenv": "17.2.3",
     "pkg-pr-new": "0.0.60",
     "rimraf": "6.1.0",
-    "tsdown": "0.16.5",
+    "tsdown": "0.16.8",
     "typescript": "5.9.3",
     "vitest": "3.2.4",
     "vitest-fetch-mock": "0.4.5"