Add nodejs_compat flag to dashboard Pages config

SvelteKit uses node:async_hooks internally; without nodejs_compat the
Pages worker throws at runtime.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tbjers

dashboard/wrangler.jsonc

@@ -1,5 +1,6 @@
 {
   "name": "coverage-tracker-dashboard",
   "compatibility_date": "2024-11-01",
+  "compatibility_flags": ["nodejs_compat"],
   "pages_build_output_dir": ".svelte-kit/cloudflare"
 }