refactor(tools): support an explicit project directory

scripts/project-root.mjs

@@ -0,0 +1,10 @@
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+/** Resolve the explicit CLI project directory, defaulting to the tool's repository. */
+export function projectRoot(moduleUrl, environment = process.env) {
+  return path.resolve(
+    environment.GEV_PROJECT_ROOT ||
+      path.join(path.dirname(fileURLToPath(moduleUrl)), '..'),
+  );
+}