Function detect_fprintd_enrolled 

pub fn detect_fprintd_enrolled() -> bool

What: Check whether a fingerprint reader is enrolled via fprintd-list.

Inputs:

• None.

Output:

• true if fprintd-list reports at least one enrolled finger.

Details:

• Runs fprintd-list $USER and checks the output for enrolled fingerprint entries.
• Returns false if fprintd-list is not installed, the command fails, or no fingers are enrolled.
• Does not require root; fprintd-list reads enrollment data via D-Bus.
• Informational only — never blocks execution.