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/object-record/object-options-dropdown/components/ObjectOptionsDropdownMenuViewName.tsx

@@ -16,8 +16,7 @@ import { styled } from '@linaria/react';
 import { useContext, useEffect, useRef, useState } from 'react';
 import { Key } from 'ts-key-enum';
 import { OverflowingTextWithTooltip, useIcons } from 'twenty-ui/display';
-import { ThemeContext } from 'twenty-ui/theme';
-import { themeCssVariables } from 'twenty-ui/theme-constants';
+import { ThemeContext, themeCssVariables } from 'twenty-ui/theme-constants';
 import { useDebouncedCallback } from 'use-debounce';
 
 const StyledDropdownMenuIconAndNameContainer = styled.div`
@@ -60,6 +59,7 @@ type ObjectOptionsDropdownMenuViewNameProps = {
 export const ObjectOptionsDropdownMenuViewName = ({
   currentView,
 }: ObjectOptionsDropdownMenuViewNameProps) => {
+  const { theme } = useContext(ThemeContext);
   const [viewPickerSelectedIcon, setViewPickerSelectedIcon] =
     useAtomComponentState(viewPickerSelectedIconComponentState);
 
@@ -111,7 +111,6 @@ export const ObjectOptionsDropdownMenuViewName = ({
     }
   }, [currentView?.key]);
 
-  const { theme } = useContext(ThemeContext);
   const { getIcon } = useIcons();
   const MainIcon = getIcon(currentView?.icon);