[BUG] Security flag lost when stronger unsecured AP found

[cachebag]

Describe the bug
In list_networks(), when deduplicating networks by (SSID, frequency), if a secured AP with weak signal is found first, then an unsecured AP with stronger signal is found, the entire network entry gets replace, losing the secured flag.

if strength > n.strength.unwrap_or(0) {
    *n = new_net.clone();  // Replaces entire struct
}

Expected behavior
Should preserve secured flag across all APs: n.secured = n.secured || new_net.secured;

Location
nmrs/src/scan.rs:88-100