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/advanced-text-editor/components/TurnIntoBlockDropdown.tsx

@@ -9,8 +9,7 @@ import { type Editor } from '@tiptap/react';
 import { useContext, useId } from 'react';
 import { IconPilcrow } from 'twenty-ui/display';
 import { MenuItem } from 'twenty-ui/navigation';
-import { ThemeContext } from 'twenty-ui/theme';
-import { themeCssVariables } from 'twenty-ui/theme-constants';
+import { ThemeContext, themeCssVariables } from 'twenty-ui/theme-constants';
 
 const StyledMenuItem = styled.button`
   align-items: center;
@@ -45,7 +44,6 @@ export const TurnIntoBlockDropdown = ({
   editor,
 }: TurnIntoBlockDropdownProps) => {
   const { theme } = useContext(ThemeContext);
-
   const instanceId = useId();
   const dropdownId = `turn-into-block-dropdown-${instanceId}`;
   const { toggleDropdown } = useToggleDropdown();
@@ -84,7 +82,7 @@ export const TurnIntoBlockDropdown = ({
         </StyledMenuItem>
       }
       dropdownOffset={{
-        y: parseInt(theme.spacing(1), 10),
+        y: parseInt(theme.spacing[1], 10),
       }}
     />
   );

packages/twenty-front/src/modules/advanced-text-editor/components/WorkflowAttachmentChip.tsx

@@ -6,8 +6,7 @@ import { useContext } from 'react';
 import { type WorkflowAttachment } from 'twenty-shared/workflow';
 import { AvatarOrIcon } from 'twenty-ui/components';
 import { IconX } 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';
 
 type WorkflowAttachmentChipProps = {
   file: WorkflowAttachment;
@@ -65,8 +64,8 @@ export const WorkflowAttachmentChip = ({
   onRemove,
   readonly = false,
 }: WorkflowAttachmentChipProps) => {
-  const iconColors = useFileCategoryColors();
   const { theme } = useContext(ThemeContext);
+  const iconColors = useFileCategoryColors();
 
   return (
     <StyledChip data-chip deletable={!readonly}>

packages/twenty-front/src/modules/advanced-text-editor/components/WorkflowSendEmailAttachments.tsx

@@ -8,8 +8,7 @@ import { type ChangeEvent, useContext, useRef } from 'react';
 import { isDefined } from 'twenty-shared/utils';
 import { type WorkflowAttachment } from 'twenty-shared/workflow';
 import { IconUpload } 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';
 
 type WorkflowSendEmailAttachmentsProps = {
   files: WorkflowAttachment[];
@@ -67,11 +66,10 @@ export const WorkflowSendEmailAttachments = ({
   label,
   onChange,
 }: WorkflowSendEmailAttachmentsProps) => {
+  const { theme } = useContext(ThemeContext);
   const fileInputRef = useRef<HTMLInputElement>(null);
   const { uploadWorkflowFile } = useUploadWorkflowFile();
   const { t } = useLingui();
-  const { theme } = useContext(ThemeContext);
-
   const handleAddFileClick = (e: React.MouseEvent) => {
     const target = e.target as HTMLElement;