fix(server): wrap file storage upsert and read in transaction (#21924)

## Summary
This PR fixes a race condition occurring during file and image uploads
in environments that use Pgpool-II or similar connection poolers with
read-replica scaling.

Currently, in `FileStorageService.writeFile`, `fileRepository.upsert`
writes the file record to the primary database node. However, the
immediate subsequent call to `fileRepository.findOneOrFail` is executed
outside of a transaction. Consequently, connection poolers like Pgpool
can route this `SELECT` query to a read-replica. Due to replication lag,
the replica may not yet reflect the newly inserted record, throwing an
`EntityNotFoundError` and failing the upload process (even though the
file is successfully saved in S3 and the database).

This PR wraps both operations in a TypeORM database transaction when
`queryRunner` is not provided. This ensures that the `SELECT` query
correctly targets the primary node, guaranteeing immediate
read-after-write consistency.

## Affected version
- Twenty Self-hosted (e.g. `v2.14.x`) configured with
Pgpool/read-replicas.

## Changes Made
- **`file-storage.service.ts`**: Wrapped `transactionalFileRepo.upsert`
and `transactionalFileRepo.findOneOrFail` within
`this.applicationRepository.manager.transaction` to ensure
read-after-write consistency.

## How to Test
1. Set up Twenty in a self-hosted environment using Pgpool configured
with load balancing / read-replicas.
2. Attempt to upload a file to a `Files` custom field or upload an image
as an organization logo.
3. Observe that the upload completes successfully without throwing an
`EntityNotFoundError` in the server logs.

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---------

Co-authored-by: Ali Bildir <[alibildir@gmail.com]>
Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-server/src/engine/core-modules/file-storage/__tests__/file-storage.service.spec.ts

@@ -23,7 +23,7 @@ describe('FileStorageService', () => {
 
   const mockFileRepository = {
     save: jest.fn(),
-    upsert: jest.fn(),
+    upsertAndReturnOne: jest.fn(),
     findOneOrFail: jest.fn(),
     delete: jest.fn(),
   };
@@ -179,7 +179,11 @@ describe('FileStorageService', () => {
         id: 'app-id',
         universalIdentifier: 'app-uid',
       });
-      mockFileRepository.upsert.mockResolvedValue(undefined);
+      mockFileRepository.upsertAndReturnOne.mockResolvedValue({
+        id: 'file-id',
+        path: 'BuiltFrontComponent/file.mjs',
+        mimeType: 'application/javascript',
+      });
       mockFileRepository.findOneOrFail.mockResolvedValue({
         id: 'file-id',
         path: 'BuiltFrontComponent/file.mjs',
@@ -442,10 +446,10 @@ describe('FileStorageService', () => {
           expect(mockDriver.writeFile).toHaveBeenCalledWith(
             expect.objectContaining({ mimeType: 'image/png' }),
           );
-          expect(mockFileRepository.upsert).toHaveBeenCalledWith(
+          expect(mockFileRepository.upsertAndReturnOne).toHaveBeenCalledWith(
             'workspace-123',
             expect.objectContaining({ mimeType: 'image/png' }),
-            expect.anything(),
+            ['path', 'workspaceId', 'applicationId'],
           );
         });
 

packages/twenty-server/src/engine/core-modules/file-storage/file-storage.service.ts

@@ -170,7 +170,7 @@ export class FileStorageService {
       sourceFile: persistedSourceFile,
     });
 
-    await fileRepository.upsert(
+    return fileRepository.upsertAndReturnOne(
       workspaceId,
       {
         path: filePath,
@@ -185,13 +185,6 @@ export class FileStorageService {
       },
       ['path', 'workspaceId', 'applicationId'],
     );
-
-    return fileRepository.findOneOrFail(workspaceId, {
-      where: {
-        path: filePath,
-        applicationId: application.id,
-      },
-    });
   }
 
   async getPresignedUrl(