Improvement: Value colour scheme improvements

[georgemac-labs]

Like approx 1 in 25 people worldwide, I have (minor) issues with shades of red and green!

The standard value colour scheme in PP is not good for me. The tones are dull, colours are recognisable if I look carefully, but you don't get the intended UI benefit of recognising them at a glance. And I am a mild case: many people would not be able to recognise the coloration at all!

Thus this PR:

1. Adds a "vivid" value colour scheme
2. Improves the settings page preview:
   • Value colours are now previewed against the actual bg colour used in app views
   • ... based on the theme selected in the dropdown
   • ... and a bug is fixed where the preview texts were not coloured in Dark mode (they were just white or grey)
3. For all views, applies update colours immediately when apply is clicked (at least Trades previously required a view switch)

TBD:

• Is this the right fix? Are the current standard colours actually a good choice as standard? To me, they seem dull compared to other apps. But it's hard for me to judge as I have non-standard vision!
• I am doing this as an accessibility amateur based on my own experience. Open to other opinions about what the exact colour values should be.

[buchen]

Value colours are now previewed against the actual bg colour used in app views

Yes, but... The text colors differ between dark and light mode. Now the preview is changing the background, but still uses the text color from the current theme. I think this is not given the right impression. The "blue text color" of the light theme does not work with the dark background color.

Unfortunately, the text color is not directly available because it is injected into the ValueColorScheme when the theme is chanted. But maybe there are ways to read the color values and apply them to the text widget? Otherwise I think it is okay to see the preview only for the current theme (light/dark) because this is what the user is using.

I am doing this as an accessibility amateur based on my own experience. Open to other opinions about what the exact colour values should be.

Me neither. For me, the bright green in the vivid light color scheme is hard to read.
But I also think that the green of the standard theme is a little bit too dark.

I am also okay to add another 4th scheme. I would need very good arguments to add a fifth.

[buchen]

Claude says there is no easy way to get the CSS colors of the text. It recommends parsing the CSS. I am not sure it is worth the effort (and future maintenance).

1. Parse the CSS files directly (recommended)

The preference page already reads CSS files (for font size in readFontSizeFromCSS()). The ValueColorScheme CSS > format is simple and stable:

ValueColorScheme.standard {
positive-foreground: #02f500;
negative-foreground: #fe2b05;
}

You could add a small method that reads dark.css / light.css and extracts the foreground colors per scheme identifier >using a regex, similar to the
existing font-size parsing. Then createSchemeOption would use the current scheme's colors OR the alternate-theme >colors depending on what
getSelectedTheme() returns. The CSS files are bundled in the plugin (css/shared/dark.css, css/shared/light.css), so > they're always available.