Replaces the 7-column <table> network list with flex div rows featuring
two-line layout (SSID + security badges on top, signal bar + meta on
bottom), coloured left-border threat indicators, and new sort controls.
Renames selectedNetwork → selectedBssid and updateNetworkTable → renderNetworks throughout wifi.js.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>