Fix sshPublicKey ObjectClassViolationError and blank OAuth parent dropdown

- User.update/addSSHkey now ensure the ldapPublicKey objectClass is present
  before writing sshPublicKey, so accounts predating that objectClass
  (e.g. the bootstrap admin) no longer 500 on PUT /api/user/:uid.
- populateHostDropdown in directory.ejs was missing an `oauth` branch,
  leaving the parent-Service picker blank when adding an OAuth Integration.
- Bump to 1.5.1.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

nodejs/package.json

@@ -1,6 +1,6 @@
 {
   "name": "t42-sso-manager",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "description": "A very simple LDAP management and SSO system",
   "author": [
     {