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-front/src/modules/file/components/FileIcon.tsx

@@ -2,11 +2,10 @@ import { type AttachmentFileCategory } from '@/activities/files/types/Attachment
 import { useFileIconColors } from '@/file/hooks/useFileIconColors';
 import { IconMapping } from '@/file/utils/fileIconMappings';
 import { styled } from '@linaria/react';
-import { useContext } from 'react';
 import { type FileCategory } from 'twenty-shared/types';
 import { AvatarOrIcon } from 'twenty-ui/components';
-import { ThemeContext } from 'twenty-ui/theme';
-import { themeCssVariables } from 'twenty-ui/theme-constants';
+import { useContext } from 'react';
+import { ThemeContext, themeCssVariables } from 'twenty-ui/theme-constants';
 
 type FileIconSize = 'small' | 'medium';
 

packages/twenty-front/src/modules/file/hooks/useFileCategoryColors.ts

@@ -3,13 +3,14 @@ import { useObjectMetadataItem } from '@/object-metadata/hooks/useObjectMetadata
 import { useContext } from 'react';
 import { CoreObjectNameSingular } from 'twenty-shared/types';
 import { isDefined } from 'twenty-shared/utils';
-import { type ThemeColor, ThemeContext } from 'twenty-ui/theme';
-
+import { ThemeContext } from 'twenty-ui/theme-constants';
+import { type ThemeColor } from 'twenty-ui/theme';
 export const useFileCategoryColors = (): Record<
   AttachmentFileCategory,
   string
 > => {
   const { theme } = useContext(ThemeContext);
+
   const { objectMetadataItem } = useObjectMetadataItem({
     objectNameSingular: CoreObjectNameSingular.Attachment,
   });
@@ -36,9 +37,11 @@ export const useFileCategoryColors = (): Record<
       if (
         isDefined(category) &&
         isDefined(color) &&
-        isDefined(theme.color[color])
+        isDefined((theme.color as unknown as Record<string, string>)[color])
       ) {
-        colorMap[category] = theme.color[color];
+        colorMap[category] = (theme.color as unknown as Record<string, string>)[
+          color
+        ];
       }
     });
   }

packages/twenty-front/src/modules/file/hooks/useFileIconColors.ts

@@ -1,7 +1,7 @@
 import { type AttachmentFileCategory } from '@/activities/files/types/AttachmentFileCategory';
 import { useContext } from 'react';
 import { type FileCategory } from 'twenty-shared/types';
-import { ThemeContext } from 'twenty-ui/theme';
+import { ThemeContext } from 'twenty-ui/theme-constants';
 
 export const useFileIconColors = (): Record<
   AttachmentFileCategory | FileCategory,