078ea0fb4b
- Add <script setup> to all 4 page components for consistent Svelte 5 syntax - Fix field name mismatches between frontend forms and backend mock API: * LanPage: dhcp_enabled -> dhcp, removed non-existent subnet field * MainRelayPage: replaced state/name/automatic/voltage/delay with lockDelayMs/unlockDelayMs * ElevatorPage: replaced floors/speed_up/speed_down/max_load with enabled/timeoutMs * DevicePage: replaced baud_rate/scanning/devices with type/sn/name/unit/room - Add saved state tracking and error display to all pages - Clean up App.svelte: remove svelte onMount import, simplify navigation logic