Rename the Police Officers Retirement Act as the Cities of the First Class Police Officers Retirement Act and change provisions of such act

This bill renames Nebraska's Police Officers Retirement Act to the "Cities of the First Class Police Officers Retirement Act" to clarify it applies only to police officers in Nebraska's largest cities (those designated as "first class"). It updates definitions throughout the law, such as specifying "city" means a first-class city employing police officers, and removes outdated provisions. The changes harmonize terminology and streamline the act without altering retirement benefit calculations or eligibility. The bill directly affects police officers in Nebraska's 13 first-class cities (e.g., Omaha, Lincoln).