feat: enforce @/ alias for imports and fix all relative parent imports (#16787)

## Summary
This PR enforces the use of `@/` alias for imports instead of relative
parent imports (`../`).

## Changes

### ESLint Configuration
- Added `no-restricted-imports` pattern in `eslint.config.react.mjs` to
block `../*` imports with the message "Relative parent imports are not
allowed. Use @/ alias instead."
- Removed the non-working `import/no-relative-parent-imports` rule
(doesn't work properly in ESLint flat config)

### VS Code Settings
- Added `javascript.preferences.importModuleSpecifier: non-relative` to
`.vscode/settings.json` (TypeScript setting was already there)

### Code Fixes
- Fixed **941 relative parent imports** across **706 files** in
`packages/twenty-front`
- All `../` imports converted to use `@/` alias

## Why
- Consistent import style across the codebase
- Easier to move files without breaking imports
- Better IDE support for auto-imports
- Clearer understanding of where imports come from

packages/twenty-front/src/modules/settings/admin-panel/config-variables/components/ConfigVariableDatabaseInput.tsx

@@ -10,7 +10,7 @@ import { type ConfigVariableValue } from 'twenty-shared/types';
 import { CustomError } from 'twenty-shared/utils';
 import { MenuItemMultiSelect } from 'twenty-ui/navigation';
 import { ConfigVariableType } from '~/generated/graphql';
-import { type ConfigVariableOptions } from '../types/ConfigVariableOptions';
+import { type ConfigVariableOptions } from '@/settings/admin-panel/config-variables/types/ConfigVariableOptions';
 
 type ConfigVariableDatabaseInputProps = {
   label: string;

packages/twenty-front/src/modules/settings/admin-panel/health-status/components/SettingsAdminWorkerHealthStatus.tsx

@@ -3,7 +3,7 @@ import styled from '@emotion/styled';
 import { t } from '@lingui/core/macro';
 import { useContext } from 'react';
 import { AdminPanelHealthServiceStatus } from '~/generated-metadata/graphql';
-import { SettingsAdminIndicatorHealthContext } from '../contexts/SettingsAdminIndicatorHealthContext';
+import { SettingsAdminIndicatorHealthContext } from '@/settings/admin-panel/health-status/contexts/SettingsAdminIndicatorHealthContext';
 
 const StyledErrorMessage = styled.div`
   color: ${({ theme }) => theme.color.red};