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/components/SettingsNavigationDrawerItem.tsx

@@ -37,7 +37,7 @@ export const SettingsNavigationDrawerItem = ({
           indentationLevel={item.indentationLevel}
           subItemState={subItemState}
           label={item.label}
-          to={href || undefined}
+          to={href}
           Icon={item.Icon}
           active={isActive}
           soon={item.soon}

packages/twenty-front/src/modules/settings/components/__stories__/CancelButton.stories.tsx

@@ -1,7 +1,7 @@
 import { type Meta, type StoryObj } from '@storybook/react';
 
 import { I18nFrontDecorator } from '~/testing/decorators/I18nFrontDecorator';
-import { CancelButton } from '../SaveAndCancelButtons/CancelButton';
+import { CancelButton } from '@/settings/components/SaveAndCancelButtons/CancelButton';
 
 const meta: Meta<typeof CancelButton> = {
   title: 'Modules/Settings/CancelButton',

packages/twenty-front/src/modules/settings/components/__stories__/SaveButton.stories.tsx

@@ -1,6 +1,6 @@
 import { type Meta, type StoryObj } from '@storybook/react';
 
-import { SaveButton } from '../SaveAndCancelButtons/SaveButton';
+import { SaveButton } from '@/settings/components/SaveAndCancelButtons/SaveButton';
 
 const meta: Meta<typeof SaveButton> = {
   title: 'Modules/Settings/SaveButton',