[Users] Add Delete User Route (DELETE /users/{userId})

[nourshoreibah]

User Story

As a user I want to delete a user from the Users table.

Description

• Add the DELETE /users/{userId} route to the users Lambda using:
  node tools/lambda-cli.js add-route users DELETE /users/{userId} --status 204
• Implement deletion logic using Kysely (db.deleteFrom('users').where('userID', '=', userId)).
• Test using Swagger and Jest.

Acceptance Criteria

• Route deletes the specified user from the local database.
• Swagger returns 204 (no content) on success.
• Jest tests verify deletion and proper 404 response for non-existent IDs.