Add automatic red and black night mode for color screens

Default to one hour after sunset through sunrise, using fresh cached GPS or recent direct RF neighbor locations. Provide saved CLI and WebConfig controls with a small integer solar approximation and no additional framebuffer.

docs/cli_command_availability.md

@@ -316,6 +316,7 @@ should use command `0x42`. See [Companion radio binary protocol](companion_proto
 | Operational | [`advert.zerohop`](cli_commands.md#send-a-zero-hop-advert) | Advert-capable role | Yes | Yes | Yes | Yes | Yes |
 | Operational | [`erase`](cli_commands.md#erasefactory-reset) | Local connection | Local | Local | Local | Local | Local |
 | Display | [`get/set display.mode`; `display.timeout`; `display.usb.mode`; `display.usb.timeout`](cli_commands.md#set-display-modes-and-timeouts) | Display-equipped roles; pairing modes require BLE Companion | Feature | Feature | Feature | Feature | Feature |
+| Night display | [`get/set display.night`; `display.night.delay`](cli_commands.md#set-display-modes-and-timeouts) | Color displays only; auto uses clock and location | Feature | Feature | Feature | Feature | Feature |
 | Display | [`get/set display.flip`](cli_commands.md#set-mqtt-observer-display-flip) | MQTT observer with supported display driver | No | No | No | Feature | No |
 | Information | [`ver`](cli_commands.md#get-the-version) | All text CLI roles | Yes | Yes | Yes | Yes | Yes |
 | Information | [`board`](cli_commands.md#show-the-hardware-name) | All text CLI roles | Yes | Yes | Yes | Yes | Yes |