BANGKOK (AP) — A two-day rally this weekend is jangling nerves in Bangkok, with apprehension about how far student demonstrators will go in pushing demands for reform of Thailand’s monarchy and how the authorities might react. More than 10,000 people are expected to attend the event. The main demands of the groups that have been holding anti-government demonstrations are a dissolution of Parliament with fresh elections, a new constitution and an end to intimidation of political activists. But the main organizers of the upcoming rally have been promoting an additional point. They want restraints on the power of the monarchy, an institution long presented as the nation’s cornerstone and untouchable.