[ALF] Theme & palette cleanup (#4769)

* Invert primary scale

* Invert negative palette

* Replace theme specific styles in Toggle

* Remove theme specific colors from Button, improves secondary solid on dark mode

* TextField

* Remove from MessageItem

* Threadgate editor

* IconCircle

* Muted words

* Generate themes from hues

* Cleanup

* Deprecate more values, fix circular import

* Invert positive too, hardly use

* Button tweaks, some theme diffs

* Match disabled state for negative button

* Fix unread noty bg

src/alf/util/colorGeneration.ts

@@ -15,3 +15,7 @@ export function generateScale(start: number, end: number) {
     return start + range * stop
   })
 }
+
+export const defaultScale = generateScale(6, 100)
+// dim shifted 6% lighter
+export const dimScale = generateScale(12, 100)