Redis lock contention on CreateDraftFromWorkflowVersion exceeds 5s retry budget

https://sonarly.com/issue/6236?type=bug

The `CreateDraftFromWorkflowVersion` mutation uses a Redis distributed lock keyed on `workflowId`. When a concurrent request for the same workflow cannot acquire the lock within 50 retries × 100ms = 5 seconds, it throws "Failed to acquire lock".

Fix: Changed `CacheLockService.withLock` to throw `ConflictException` (NestJS 409) instead of a plain `Error` when lock acquisition fails after max retries.

**Why this fixes the bug:**
- `ConflictException` is an `HttpException` with status 409, which the existing exception pipeline handles correctly:
  - `shouldCaptureException` returns `false` for `HttpException` with status < 500 → **stops noisy Sentry alerts**
  - `convertHttpExceptionToGraphql` maps 409 to `ConflictError` → **user sees "Conflict" instead of "Internal Server Error"**
- Lock contention is semantically a conflict (two requests competing for the same resource), making 409 the correct HTTP status

**What this does NOT change:**
- Lock timing parameters (ms, maxRetries, ttl) remain unchanged — those were deliberately tuned in commits ee648197df and f131a86cc5
- The retry logic is unchanged — the fix only changes the exception type after retries are exhausted

Updated the test to assert `ConflictException` type instead of error message string matching.

packages/twenty-server/src/engine/core-modules/cache-lock/__tests__/cache-lock.service.spec.ts

@@ -1,3 +1,4 @@
+import { ConflictException } from '@nestjs/common';
 import { Test, type TestingModule } from '@nestjs/testing';
 
 import { CacheLockService } from 'src/engine/core-modules/cache-lock/cache-lock.service';
@@ -58,7 +59,7 @@ describe('CacheLockService', () => {
     expect(cacheStorageService.releaseLock).toHaveBeenCalledWith('key');
   });
 
-  it('should throw an error if lock cannot be acquired after max retries', async () => {
+  it('should throw a ConflictException if lock cannot be acquired after max retries', async () => {
     cacheStorageService.acquireLock.mockResolvedValue(false);
 
     const fn = jest.fn();
@@ -67,7 +68,7 @@ describe('CacheLockService', () => {
 
     await expect(
       service.withLock(fn, 'key', { ms, maxRetries }),
-    ).rejects.toThrow('Failed to acquire lock for key: key');
+    ).rejects.toThrow(ConflictException);
 
     expect(cacheStorageService.acquireLock).toHaveBeenCalledTimes(maxRetries);
     expect(fn).not.toHaveBeenCalled();

packages/twenty-server/src/engine/core-modules/cache-lock/cache-lock.service.ts

@@ -1,4 +1,4 @@
-import { Injectable } from '@nestjs/common';
+import { ConflictException, Injectable } from '@nestjs/common';
 
 import { InjectCacheStorage } from 'src/engine/core-modules/cache-storage/decorators/cache-storage.decorator';
 import { CacheStorageNamespace } from 'src/engine/core-modules/cache-storage/types/cache-storage-namespace.enum';
@@ -42,6 +42,6 @@ export class CacheLockService {
       await this.delay(ms);
     }
 
-    throw new Error(`Failed to acquire lock for key: ${key}`);
+    throw new ConflictException(`Failed to acquire lock for key: ${key}`);
   }
 }