Complete linaria migration (#18361)

## Summary

Completes the migration of the frontend styling system from **Emotion**
(`@emotion/styled`, `@emotion/react`) to **Linaria** (`@linaria/react`,
`@linaria/core`), a zero-runtime CSS-in-JS library where styles are
extracted at build time.

This is the final step of the migration — all ~494 files across
`twenty-front`, `twenty-ui`, `twenty-website`, and `twenty-sdk` are now
fully converted.

## Changes

### Styling Migration (across ~480 component files)
- Replaced all `@emotion/styled` imports with `@linaria/react`
- Converted runtime theme access patterns (`({ theme }) => theme.x.y`)
to build-time `themeCssVariables` CSS custom properties
- Replaced `useTheme()` hook (from Emotion) with
`useContext(ThemeContext)` where runtime theme values are still needed
(e.g., passing colors to non-CSS props like icon components)
- Removed `@emotion/react` `css` helper usages in favor of Linaria
template literals

### Dependency & Configuration Changes
- **Removed**: `@emotion/react`, `@emotion/styled` from root
`package.json`
- **Added**: `@wyw-in-js/babel-preset`, `next-with-linaria` (for
twenty-website SSR support)
- Updated Nx generator defaults from `@emotion/styled` to
`@linaria/react` in `nx.json`
- Simplified `vite.config.ts` (removed Emotion-specific configuration)
- Updated `twenty-website/next.config.js` to use `next-with-linaria` for
SSR Linaria support

### Storybook & Testing
- Removed `ThemeProvider` from Emotion in Storybook previews
(`twenty-front`, `twenty-sdk`)
- Now relies solely on `ThemeContextProvider` for theme injection

### Documentation
- Removed the temporary `docs/emotion-to-linaria-migration-plan.md`
(migration complete)
- Updated `CLAUDE.md` and `README.md` to reflect Linaria as the styling
stack
- Updated frontend style guide docs across all locales

## How it works

Linaria extracts styles at build time via the `@wyw-in-js/vite` plugin.
All expressions in `styled` template literals must be **statically
evaluable** — no runtime theme objects or closures over component state.

- **Static styles** use `themeCssVariables` which map to CSS custom
properties (`var(--theme-color-x)`)
- **Runtime theme access** (for non-CSS use cases like icon `color`
props) uses `useContext(ThemeContext)` instead of Emotion's `useTheme()`

packages/twenty-front/src/modules/object-record/object-options-dropdown/components/ObjectOptionsDropdownMenuViewName.tsx

@@ -12,11 +12,12 @@ import { useUpdateViewFromCurrentState } from '@/views/view-picker/hooks/useUpda
 import { viewPickerIsDirtyComponentState } from '@/views/view-picker/states/viewPickerIsDirtyComponentState';
 import { viewPickerIsPersistingComponentState } from '@/views/view-picker/states/viewPickerIsPersistingComponentState';
 import { viewPickerSelectedIconComponentState } from '@/views/view-picker/states/viewPickerSelectedIconComponentState';
-import { useTheme } from '@emotion/react';
-import styled from '@emotion/styled';
-import { useEffect, useRef, useState } from 'react';
+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 { useDebouncedCallback } from 'use-debounce';
 
 const StyledDropdownMenuIconAndNameContainer = styled.div`
@@ -24,27 +25,27 @@ const StyledDropdownMenuIconAndNameContainer = styled.div`
   display: flex;
   margin-left: 0;
   margin-right: 0;
-  gap: ${({ theme }) => theme.spacing(1)};
+  gap: ${themeCssVariables.spacing[1]};
 `;
 
 const StyledMenuTitleContainer = styled.div`
   align-items: center;
   display: flex;
-  gap: ${({ theme }) => theme.spacing(1)};
-  padding: ${({ theme }) => theme.spacing(1)};
+  gap: ${themeCssVariables.spacing[1]};
+  padding: ${themeCssVariables.spacing[1]};
 `;
 
 const StyledMenuIconContainer = styled.div`
-  color: ${({ theme }) => theme.font.color.primary};
+  color: ${themeCssVariables.font.color.primary};
   align-items: center;
   display: flex;
-  height: ${({ theme }) => theme.spacing(6)};
+  height: ${themeCssVariables.spacing[6]};
   justify-content: center;
-  width: ${({ theme }) => theme.spacing(6)};
+  width: ${themeCssVariables.spacing[6]};
 `;
 
 const StyledMainText = styled.div`
-  color: ${({ theme }) => theme.font.color.primary};
+  color: ${themeCssVariables.font.color.primary};
   flex-shrink: 0;
   overflow: hidden;
   text-overflow: ellipsis;
@@ -110,7 +111,7 @@ export const ObjectOptionsDropdownMenuViewName = ({
     }
   }, [currentView?.key]);
 
-  const theme = useTheme();
+  const { theme } = useContext(ThemeContext);
   const { getIcon } = useIcons();
   const MainIcon = getIcon(currentView?.icon);