Prevent csv export injections (#14347)

**Small Security Issue:** CSV exports were vulnerable to formula
injection attacks when users entered values starting with =, +, -, or @.
(only happens if a logged-in user injects corrupted data)

Solution:
- Added ZWJ (Zero-Width Joiner) protection that prefixes dangerous
values with invisible Unicode character
- This is the best way to preserve original data while preventing Excel
from executing formulas
- Added import cleanup to restore original values when re-importing
 
Changes:
- New sanitizeValueForCSVExport() function for security
- Updated all CSV export paths to use both security + formatting
functions
- Added comprehensive tests covering attack vectors and international
characters
- Also added cursor rules for better code consistency

---------

Co-authored-by: Charles Bochet <charlesBochet@users.noreply.github.com>

packages/twenty-front/src/testing/constants/UntestedAppPaths.ts

@@ -1,3 +1,3 @@
-import { AppPath } from 'twenty-shared/types';
+import { AppPath } from '@/types/AppPath';
 
 export const UNTESTED_APP_PATHS = [AppPath.Settings, AppPath.Developers];