> Add a /api/login endpoint that creates a session for a user

from flask import jsonify, request
from flask_login import LoginManager, login_user
from app import app

login_manager = LoginManager(app)
@app.route('/api/login', methods=['POST'])
def login():
    """Handle user login and create session."""
    data = request.get_json()
    user = User.query.filter_by(username=data['username']).first()
    if user and user.password == data['password']:
        login_user(user)
        return jsonify({'status': 'success'})
    return jsonify({'error': 'Invalid credentials'}), 401