fix: import sshpk as a default so the backend starts under ESM

src/backend/tests/utils/ssh-key-utils.test.ts

@@ -1,6 +1,6 @@
 import { generateKeyPairSync } from "node:crypto";
 import ssh2 from "ssh2";
-import { parsePrivateKey } from "sshpk";
+import sshpk from "sshpk";
 import { describe, it, expect } from "vitest";
 import { readFileSync } from "node:fs";
 import {
@@ -12,6 +12,8 @@ import {
   validateKeyPair,
 } from "../../utils/ssh-key-utils.js";
 
+const { parsePrivateKey } = sshpk;
+
 // A real OpenSSH ed25519 keypair generated solely for these tests. It grants no
 // access to anything and exists only so the ssh2 parsing path is exercised for
 // real rather than only via the text-fallback heuristics.

src/backend/utils/ssh-key-utils.ts

@@ -1,8 +1,9 @@
 import { createPrivateKey } from "node:crypto";
-import { parsePrivateKey } from "sshpk";
+import sshpk from "sshpk";
 import { getErrorMessage } from "./error-message.js";
 import ssh2Pkg from "ssh2";
 const ssh2Utils = ssh2Pkg.utils;
+const { parsePrivateKey } = sshpk;
 
 function detectKeyTypeFromContent(keyContent: string): string {
   const content = keyContent.trim();