[DevXP] Improve Linaria pre-build speed (#18382)

## Summary

This PR improves Linaria/WYW pre-build speed and continues the migration
of `twenty-ui` components away from runtime `ThemeContext` reads toward
static CSS variables and theme constants.

### Linaria/WYW profiling plugin improvements (`twenty-shared`)

- **Babel JIT warmup**: added a `buildStart` warmup step that triggers
WYW's Babel JIT compilation before the real build starts, so the first
real file doesn't pay the cold-start penalty
- **`configResolved` hook**: detects dev vs prod mode and resolves the
correct warmup file path relative to `config.root`
- **Dev-only per-file logging**: slow file warnings are now gated behind
`isDevMode`, keeping production/CI build output clean
- **`closeBundle` summary**: moved the final top-slow-files report to
`closeBundle` for accurate end-of-build reporting
- **Removed noisy progress interval logging** in favor of the warmup log
+ final summary

### Migration from `ThemeContext` to static CSS variables / constants

Across `twenty-ui`, replaced runtime `useTheme()` reads with:
- `themeCssVariables` CSS custom properties (colors, spacing)
- Hard-coded design-system constants (`ICON.size.md` → `16`,
`ICON.stroke.sm` → `1.6`) so components no longer need a React context
at render time — enabling Linaria static extraction

**Components migrated:**
- `Button`, `AnimatedButton`, `LightButton`, `LightIconButton`,
`AnimatedLightIconButton`, `ButtonIcon`, `ButtonSoon`
- `ProgressBar` (Framer Motion width animation → CSS `transition`)
- `Info`, `HorizontalSeparator`, `LinkChip`
- `MenuPicker`, `MenuItemLeftContent`, `MenuItemIconWithGripSwap`,
`NavigationBarItem`
- `JsonArrow`, `JsonNestedNode`
- `ModalHeader`

### Other
- Added `aria-valuenow` to `ProgressBar` for accessibility
- `VisibilityHidden` component updated to inline accessibility styles

packages/twenty-ui/src/input/button/components/LightIconButton.tsx

@@ -1,8 +1,7 @@
 import { styled } from '@linaria/react';
 import { type IconComponent } from '@ui/display';
-import { ThemeContext } from '@ui/theme';
-import { themeCssVariables } from '@ui/theme-constants';
-import { type ComponentProps, type MouseEvent, useContext } from 'react';
+import { ICON_SIZES, themeCssVariables } from '@ui/theme-constants';
+import { type ComponentProps, type MouseEvent } from 'react';
 
 export type LightIconButtonAccent = 'secondary' | 'tertiary';
 export type LightIconButtonSize = 'small' | 'medium';
@@ -106,8 +105,6 @@ export const LightIconButton = ({
   onClick,
   title,
 }: LightIconButtonProps) => {
-  const { theme } = useContext(ThemeContext);
-
   return (
     <StyledButton
       data-testid={testId}
@@ -122,9 +119,7 @@ export const LightIconButton = ({
       title={title}
     >
       {Icon && (
-        <Icon
-          size={size === 'medium' ? theme.icon.size.md : theme.icon.size.sm}
-        />
+        <Icon size={size === 'medium' ? ICON_SIZES.md : ICON_SIZES.sm} />
       )}
     </StyledButton>
   );