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/apollo/utils/__tests__/formatTitle.test.ts

@@ -1,6 +1,6 @@
 import { OperationType } from '@/apollo/types/operation-type';
 
-import formatTitle from '../formatTitle';
+import formatTitle from '@/apollo/utils/formatTitle';
 
 describe('formatTitle', () => {
   it('should correctly format the title', () => {

packages/twenty-front/src/modules/apollo/utils/__tests__/getTokenPair.test.ts

@@ -1,5 +1,5 @@
 import { cookieStorage } from '~/utils/cookie-storage';
-import { getTokenPair } from '../getTokenPair';
+import { getTokenPair } from '@/apollo/utils/getTokenPair';
 
 jest.mock('~/utils/cookie-storage', () => ({
   cookieStorage: {

packages/twenty-front/src/modules/apollo/utils/__tests__/hasTokenPair.test.ts

@@ -1,5 +1,5 @@
-import { getTokenPair } from '../getTokenPair';
-import { hasTokenPair } from '../hasTokenPair';
+import { getTokenPair } from '@/apollo/utils/getTokenPair';
+import { hasTokenPair } from '@/apollo/utils/hasTokenPair';
 
 jest.mock('../getTokenPair');
 

packages/twenty-front/src/modules/apollo/utils/__tests__/streamingRestLink.test.ts

@@ -1,6 +1,6 @@
 import { gql } from '@apollo/client';
 import { type Operation } from '@apollo/client/core';
-import { StreamingRestLink } from '../streamingRestLink';
+import { StreamingRestLink } from '@/apollo/utils/streamingRestLink';
 
 global.fetch = jest.fn();
 describe('StreamingRestLink', () => {

packages/twenty-front/src/modules/apollo/utils/formatTitle.ts

@@ -1,4 +1,4 @@
-import { OperationType } from '../types/operation-type';
+import { OperationType } from '@/apollo/types/operation-type';
 
 const operationTypeColors = {
   // eslint-disable-next-line @nx/workspace-no-hardcoded-colors