fix: align windows safe-open file identity checks

src/infra/file-identity.ts

@@ -0,0 +1,25 @@
+export type FileIdentityStat = {
+  dev: number | bigint;
+  ino: number | bigint;
+};
+
+function isZero(value: number | bigint): boolean {
+  return value === 0 || value === 0n;
+}
+
+export function sameFileIdentity(
+  left: FileIdentityStat,
+  right: FileIdentityStat,
+  platform: NodeJS.Platform = process.platform,
+): boolean {
+  if (left.ino !== right.ino) {
+    return false;
+  }
+
+  // On Windows, path-based stat calls can report dev=0 while fd-based stat
+  // reports a real volume serial; treat either-side dev=0 as "unknown device".
+  if (left.dev === right.dev) {
+    return true;
+  }
+  return platform === "win32" && (isZero(left.dev) || isZero(right.dev));
+}