Options for selecting dark theme, fix some white flashes when in dark mode (#2722)

* add dark theme selection to settings/schema

* use `useThemePrefs` where needed

* adjust theme providers to support various themes

* update storybook

* handle web themes

* better themeing for web

* dont show dark theme prefs when color mode is light

* drop the inverted text change on oled theme

* get the color mode inside of `useColorModeTheme`

* use `ThemeName` type everywhere

* typo

* use dim/dark instead of dark/oled

* prevent any fickers on web

* fix styles

* use `dim` for dark default

* more cleanup

* 🤔

* set system background color

* ts

src/lib/themes.ts

@@ -2,7 +2,7 @@ import {Platform} from 'react-native'
 import type {Theme} from './ThemeContext'
 import {colors} from './styles'
 
-import {darkPalette, lightPalette} from '#/alf/themes'
+import {darkPalette, lightPalette, dimPalette} from '#/alf/themes'
 
 export const defaultTheme: Theme = {
   colorScheme: 'light',
@@ -336,3 +336,14 @@ export const darkTheme: Theme = {
     },
   },
 }
+
+export const dimTheme: Theme = {
+  ...darkTheme,
+  palette: {
+    ...darkTheme.palette,
+    default: {
+      ...darkTheme.palette.default,
+      background: dimPalette.black,
+    },
+  },
+}