chore(twenty-front): migrate command-menu, workflow, page-layout and UI modules from Emotion to Linaria (PR 4-6/10) (#18342)

## Summary

Continues the Emotion → Linaria migration (PR 4-6 from the [migration
plan](docs/emotion-to-linaria-migration-plan.md)). Migrates **311
files** across four module groups:

| Module | Files |
|---|---|
| command-menu | 53 |
| workflow | 84 |
| page-layout | 84 |
| UI (partial - first ~80 files) | ~80 |
| twenty-ui (TEXT_INPUT_STYLE) | 1 |
| misc (hooks, keyboard-shortcut-menu, file-upload) | ~9 |

### Migration patterns applied

- `import styled from '@emotion/styled'` → `import { styled } from
'@linaria/react'`
- `import { useTheme } from '@emotion/react'` → `import { useContext }
from 'react'` + `import { ThemeContext } from 'twenty-ui/theme'`
- `${({ theme }) => theme.X.Y.Z}` → `${themeCssVariables.X.Y.Z}` (static
CSS variables)
- `theme.spacing(N)` → `themeCssVariables.spacing[N]`
- `styled(motion.div)` → `motion.create(StyledBase)` (11 components)
- `styled(Component)<TypeParams>` → wrapper div approach for non-HTML
elements
- Multi-declaration interpolations split into one CSS property per
interpolation
- Interpolation return types fixed (`&&` → ternary `? : ''`)
- `TEXT_INPUT_STYLE` converted from function to static string constant
(backward compatible)
- Emotion `<Global>` replaced with `useEffect` style injection
- Complex runtime-dependent styles use CSS custom properties via
`style={}` prop

### After this PR

- **Remaining files**: ~400 (object-record: ~160, settings: ~200, UI:
~44)
- **No breaking changes**: CSS variables resolve identically to the
previous Emotion theme values

packages/twenty-front/src/modules/ui/layout/dropdown/components/DropdownMenuItemsContainer.tsx

@@ -1,10 +1,11 @@
 import { DROPDOWN_MENU_ITEMS_CONTAINER_MAX_HEIGHT } from '@/ui/layout/dropdown/constants/DropdownMenuItemsContainerMaxHeight';
-import styled from '@emotion/styled';
+import { styled } from '@linaria/react';
+import { themeCssVariables } from 'twenty-ui/theme-constants';
 
 const StyledExternalContainer = styled.div<{
   maxHeight?: number;
 }>`
-  --padding: ${({ theme }) => theme.spacing(1)};
+  --padding: ${themeCssVariables.spacing[1]};
 
   align-items: flex-start;
   display: flex;
@@ -28,11 +29,11 @@ const StyledScrollableContainer = styled.div<{ maxHeight?: number }>`
   width: 100%;
 
   overflow-y: auto;
-  scrollbar-color: ${({ theme }) => theme.border.color.medium} transparent;
+  scrollbar-color: ${themeCssVariables.border.color.medium} transparent;
   scrollbar-width: 4px;
 
   *::-webkit-scrollbar-thumb {
-    border-radius: ${({ theme }) => theme.border.radius.sm};
+    border-radius: ${themeCssVariables.border.radius.sm};
   }
 `;