Function get_machine_display_name 

pub fn get_machine_display_name(db: &Database, machine_id: &str) -> String

Returns a display-friendly name for a machine ID.

First queries the machines table to find a registered name. If not found, falls back to checking if this is the current machine and uses the config. Otherwise returns the machine_id truncated to first 8 characters for readability.

This function is designed for use in session listings to show human-readable machine names instead of UUIDs.