Add standalone mode with @simpleworkjs/orm-backed user/host stores

- Add standalone.enabled config flag to switch between LDAP+SSO and
  ORM-backed backends without changing the production code path
- New ORM models: StandaloneUser (uid, passwordHash, sshPublicKeys,
  groups) and StandaloneHost (slug, displayName, kind, metadata)
- user_file.js and hosts_file.js implement the same interfaces as the
  LDAP client and accessibleHosts() respectively
- models/user_ldap.js and utils/access.js become conditional facades
  that delegate based on conf.standalone.enabled at require time
- Zero changes to ssh_server.js core logic, bridge.js, key_inject.js,
  tui_picker.js, or any other consumer
- Fix ssh_server.js: use ?? instead of || for listenPort (0 is falsy)
- Fix ssh_server.js: register session listeners before awaiting
  audit.create() so client exec/shell requests aren't rejected
- Patch StringField.toSequelize() and IntegerField.toSequelize() to
  pass through primaryKey (the ORM's UUIDField already does this)
- 47 tests pass (24 existing + 15 new unit + 3 existing integration
  + 5 new standalone integration)
- Defaults to SQLite; any Sequelize dialect works via conf.orm

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

nodejs/models/index.js

@@ -49,4 +49,18 @@ module.exports.authRouter = oidcClient.router;
 require('./audit_event');
 
 // Idempotent anti-lockout local admin (was the IIFE in user_redis.js).
-bootstrapLocalAdmin(Table.models.User, { defaultName: 'jumpadmin' });
+bootstrapLocalAdmin(Table.models.User, { defaultName: 'jumpadmin' });
+
+// Standalone mode: initialize @simpleworkjs/orm for local user/host stores.
+// The ORM must be loaded before any code calls user_ldap or access — both of
+// which check conf.standalone.enabled at require time and may delegate to the
+// ORM-backed wrappers. Model registration is synchronous; table sync is async
+// but the first query will implicitly wait (Sequelize.sync is in-flight).
+// Export the promise so integration tests can await it before seeding data.
+let ormReady = Promise.resolve();
+if (conf.standalone && conf.standalone.enabled) {
+	const { init } = require('@simpleworkjs/orm');
+	const ormConf = conf.orm || { dialect: 'sqlite', storage: './data/standalone.sqlite', logging: false };
+	ormReady = init({ conf: { orm: ormConf }, models: [require('./standalone_user'), require('./standalone_host')] });
+}
+module.exports.ormReady = ormReady;