apps/settings: convey network-access CLI + settings UI block
Add the convey settings CLI surface plus the restart-aware security controls in the settings app. This wires the new network-access, trust-localhost, and host-url flows through one config surface while keeping the password refusal rules and effective host URL responses consistent across CLI and UI.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>