Delete leasing contract

Deletes or cancels a leasing contract depending on its current status.

Behavior based on contract status:

• Created status: The contract is permanently deleted from the database.
  This is only possible when the contract has not yet been activated or had
  any financial transactions.

• Other statuses (move_in, in_progress, move_out): The contract is cancelled
  rather than deleted. This process:

  • Sets the contract status to 'closed'
  • Destroys any first rent accounting event groups (if no payments received)
  • Cancels any active signature requests
  • Creates a system log message documenting the cancellation

Important: Contracts that have received payments on their last accounting
event group cannot be cancelled and will return an error.

This endpoint is useful for:

• Removing draft contracts that were created by mistake
• Cancelling contracts before move-in when the tenant backs out
• Cleaning up test data in development environments