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/modules/settings/developers/hooks/useWebhookForm.ts

@@ -12,10 +12,10 @@ import {
   webhookFormSchema,
   type WebhookFormValues,
 } from '@/settings/developers/validation-schemas/webhookFormSchema';
+import { SettingsPath } from '@/types/SettingsPath';
 import { useSnackBar } from '@/ui/feedback/snack-bar-manager/hooks/useSnackBar';
 import { ApolloError } from '@apollo/client';
 import { t } from '@lingui/core/macro';
-import { SettingsPath } from 'twenty-shared/types';
 import {
   useCreateWebhookMutation,
   useDeleteWebhookMutation,