fix: replace slow deep-equal with fastDeepEqual to resolve CPU bottleneck (#19771)

## Summary

- Replaced the `deep-equal` npm package with the existing
`fastDeepEqual` from `twenty-shared/utils` across 5 files in the server
and shared packages
- `deep-equal` was causing severe CPU overhead in the record update hot
path (`executeMany` → `formatTwentyOrmEventToDatabaseBatchEvent` →
`objectRecordChangedValues` → `deepEqual`, called **per field per
record**)
- `fastDeepEqual` is ~100x faster for plain JSON database records since
it skips unnecessary prototype chain inspection and edge-case handling
- Removed the now-unnecessary `LARGE_JSON_FIELDS` branching in
`objectRecordChangedValues` since all fields now use the fast
implementation

packages/twenty-shared/src/utils/compute-diff-between-objects.ts

@@ -1,5 +1,6 @@
 import { isDefined } from '@/utils/validation';
-import deepEqual from 'deep-equal';
+
+import { fastDeepEqual } from './json/fast-deep-equal';
 
 type Diff<T extends { id: string }> = {
   toCreate: T[];
@@ -67,7 +68,9 @@ export const computeDiffBetweenObjects = <
           propertiesToCompare,
         );
 
-        if (!deepEqual(comparableExistingEntity, comparableReceivedEntity)) {
+        if (
+          !fastDeepEqual(comparableExistingEntity, comparableReceivedEntity)
+        ) {
           toUpdate.push(receivedObject);
         }
       }