Describe the bug
I came across issue #707 while looking for a solution on how to improve the readability of logs in SMAPI console and then followed the suggestion to add config.user.json. I added the file and changed the contents to my liking, but smapi still used the old color scheme. I also added SMAPI-config.json in the Mods folder to make sure that the documentation was correct, but the color scheme also remained unchanged. I only realized the bug after forcing to change all text colors in the scheme (both in dark and light backgrounds) to white. I re-edited my configuration and realized that SMAPI only reads the color scheme for light backgrounds.

To Reproduce

1. add smapi-internal/config.user.json or Mods/SMAPI-config.json file with customized settings. the following is the initial configuration:

{
   "ConsoleColors": {
      "UseScheme": "None"
   }
}

3. launch smapi and see that the color scheme has not changed.
4. change the color settings with the following scheme:

{
    "ConsoleColors": {
        "UseScheme": "DarkBackground",

        "Schemes": {
            "DarkBackground": {
                "Trace": "White",
                "Debug": "White",
                "Info": "White",
                "Warn": "White",
                "Error": "White",
                "Alert": "White",
                "Success": "White"
            },
            "LightBackground": {
                "Trace": "Gray",
                "Debug": "Gray",
                "Info": "White",
                "Warn": "Yellow",
                "Error": "Red",
                "Alert": "Magenta",
                "Success": "Green"
            }
        }
    }
}

6. launch smapi and notice that now the colors have changed.

Log file
https://smapi.io/log/b5eb4419a1b844f8863f0d40409efbe8

Screenshots
The result using initial configuration:

The result using later configuration:

I have tested this too; running on xterm. It is not respecting the json files.

Fixed in the upcoming SMAPI 4.1.9. Thanks for reporting it!