Function read_proc_start_time_ns 

pub fn read_proc_start_time_ns(pid: u32) -> u64

Read the process start time in nanoseconds from /proc/{pid}/stat.

Returns 0 if the process doesn’t exist or parsing fails. The value is jiffies-since-boot converted to nanoseconds.

Internal Usage

This function is used internally by parse_proc_entry to populate the start_time_ns field of super::types::ProcessInfo.