Deprecate runtime theme objects in favor of CSS variables (#18402)

## Summary

- **Eliminate `ICON_SIZES` / `ICON_STROKES` constants**: all icon
dimensions are now resolved at runtime via
`resolveThemeVariableAsNumber(themeCssVariables.icon.size.X)`, ensuring
values always come from computed CSS variables
- **No more consumer imports from `twenty-ui/theme`**: moved
`ColorSchemeContext`, `ColorSchemeProvider`, `ThemeColor`,
`MAIN_COLOR_NAMES`, `getNextThemeColor`, `AnimationDuration` to
`twenty-ui/theme-constants`
- **Remove `ThemeContext` / `ThemeContextProvider` / `ThemeProvider` /
`ThemeType`**: replaced across ~300 files with `themeCssVariables` (for
CSS contexts) or `resolveThemeVariable` / `resolveThemeVariableAsNumber`
(for JS runtime values)
- **Simplify provider chain**: only `ColorSchemeProvider` remains — it
toggles `light`/`dark` class on `document.documentElement` and provides
`colorScheme` via React context
- **Fix pre-existing test failures**: `useIcons.test.ts`
(non-configurable ES module spy) and
`turnRecordFilterGroupIntoGqlOperationFilter.test.ts`
(`Omit<RecordFilter, 'id'>` type mismatch)

### Theme access pattern (before → after)

| Context | Before | After |
|---------|--------|-------|
| CSS (Linaria) | `${({ theme }) => theme.font.color.primary}` |
`${themeCssVariables.font.color.primary}` |
| JS runtime (icon size, animation) | `theme.icon.size.md` /
`ICON_SIZES.md` |
`resolveThemeVariableAsNumber(themeCssVariables.icon.size.md)` |
| Color scheme check | `theme.name === 'dark'` |
`useContext(ColorSchemeContext).colorScheme === 'dark'` |

packages/twenty-ui/src/components/avatar-or-icon/AvatarOrIcon.tsx

@@ -2,9 +2,9 @@ import { styled } from '@linaria/react';
 import { Avatar } from '@ui/display/avatar/components/Avatar';
 import { type AvatarType } from '@ui/display/avatar/types/AvatarType';
 import { type IconComponent } from '@ui/display/icon/types/IconComponent';
-import { ThemeContext } from '@ui/theme';
-import { type Nullable } from '@ui/utilities';
+import { ThemeContext } from '@ui/theme-constants';
 import { useContext } from 'react';
+import { type Nullable } from '@ui/utilities';
 import { isDefined } from 'twenty-shared/utils';
 
 const StyledIconWithBackgroundContainer = styled.div<{
@@ -50,6 +50,7 @@ export const AvatarOrIcon = ({
   onClick,
 }: AvatarOrIconProps) => {
   const { theme } = useContext(ThemeContext);
+
   if (!isDefined(Icon)) {
     return (
       <Avatar

packages/twenty-ui/src/components/tag/Tag.tsx

@@ -1,11 +1,11 @@
 import { styled } from '@linaria/react';
-import { useContext } from 'react';
 
 import { type IconComponent } from '@ui/display/icon/types/IconComponent';
 import { OverflowingTextWithTooltip } from '@ui/display/tooltip/OverflowingTextWithTooltip';
-import { type ThemeColor, ThemeContext } from '@ui/theme';
-import { themeCssVariables } from '@ui/theme-constants';
 import { isDefined } from 'twenty-shared/utils';
+import { type ThemeColor } from '@ui/theme';
+import { ThemeContext, themeCssVariables } from '@ui/theme-constants';
+import { useContext } from 'react';
 
 const StyledTag = styled.h3<{
   color: TagColor;

packages/twenty-ui/src/components/tag/__stories__/Tag.stories.tsx

@@ -7,7 +7,7 @@ import {
   type CatalogStory,
   ComponentDecorator,
 } from '@ui/testing';
-import { MAIN_COLOR_NAMES, type ThemeColor } from '@ui/theme';
+import { type ThemeColor, MAIN_COLOR_NAMES } from '@ui/theme';
 
 import { Tag } from '../Tag';