fix(contributors): address Copilot review comments and code quality issues

- Improve contributor-report.mjs based on Copilot comments and sonar
- Use fileURLToPath for Windows-safe main checks in contributor scripts
- Fix README badge URLs by removing duplicate style parameters
- Update graceful-shutdown.mjs to throw on process.exit failure for better error visibility

Generated-by: GitHub Copilot <copilot@github.com>
Signed-off-by: Ashley Childress <6563688+anchildress1@users.noreply.github.com>

eng/utils/graceful-shutdown.mjs

@@ -26,8 +26,9 @@ export const setupGracefulShutdown = (name, { exitCode = 1 } = {}) => {
     try {
       process.exit(exitCode);
     } catch (e) {
-      // process.exit may not be desirable in some test harnesses; swallow errors
-      console.warn(`${name}: process.exit failed:`, e?.message);
+      // If process.exit is stubbed or overridden (e.g. in tests), surface the failure.
+      console.error(`${name}: process.exit failed:`, e?.message || e);
+      throw e;
     }
   };