Remove DataSourceService and clean up datasource migration logic (#19532)

## Summary

- **Drop the `objectMetadata.dataSourceId` foreign key and index** via a
1-22 fast instance command — column kept nullable for data preservation
- **Delete `DataSourceService`, `DataSourceModule`, and
`DataSourceException`** — all code now uses `workspace.databaseSchema`
directly
- **Remove `IS_DATASOURCE_MIGRATED` feature flag** from default flags
and all branching logic
- **Simplify workspace/object creation pipelines** —
`WorkspaceManagerService`, `DevSeederService`, and the object creation
action handler no longer route through `DataSourceService`
- **Keep `DataSourceEntity` and the `dataSource` table** for historical
data — entity stripped of all ORM relations

packages/twenty-server/src/engine/api/graphql/workspace-graphql-schema-sdl/workspace-graphql-schema-sdl.module.ts

@@ -3,8 +3,6 @@ import { Module } from '@nestjs/common';
 import { ScalarsExplorerService } from 'src/engine/api/graphql/services/scalars-explorer.service';
 import { WorkspaceSchemaBuilderModule } from 'src/engine/api/graphql/workspace-schema-builder/workspace-schema-builder.module';
 import { WorkspaceGraphqlSchemaSDLService } from 'src/engine/api/graphql/workspace-graphql-schema-sdl/workspace-graphql-schema-sdl.service';
-import { FeatureFlagModule } from 'src/engine/core-modules/feature-flag/feature-flag.module';
-import { DataSourceModule } from 'src/engine/metadata-modules/data-source/data-source.module';
 import { WorkspaceManyOrAllFlatEntityMapsCacheModule } from 'src/engine/metadata-modules/flat-entity/services/workspace-many-or-all-flat-entity-maps-cache.module';
 import { WorkspaceCacheStorageModule } from 'src/engine/workspace-cache-storage/workspace-cache-storage.module';
 
@@ -13,8 +11,6 @@ import { WorkspaceCacheStorageModule } from 'src/engine/workspace-cache-storage/
     WorkspaceSchemaBuilderModule,
     WorkspaceCacheStorageModule,
     WorkspaceManyOrAllFlatEntityMapsCacheModule,
-    FeatureFlagModule,
-    DataSourceModule,
   ],
   providers: [WorkspaceGraphqlSchemaSDLService, ScalarsExplorerService],
   exports: [WorkspaceGraphqlSchemaSDLService],

packages/twenty-server/src/engine/api/graphql/workspace-graphql-schema-sdl/workspace-graphql-schema-sdl.service.ts

@@ -2,14 +2,11 @@ import { Injectable } from '@nestjs/common';
 
 import { isNonEmptyString } from '@sniptt/guards';
 import { printSchema } from 'graphql';
-import { FeatureFlagKey } from 'twenty-shared/types';
 import { isDefined } from 'twenty-shared/utils';
 
 import { ScalarsExplorerService } from 'src/engine/api/graphql/services/scalars-explorer.service';
 import { WorkspaceGraphQLSchemaGenerator } from 'src/engine/api/graphql/workspace-schema-builder/workspace-graphql-schema.factory';
-import { FeatureFlagService } from 'src/engine/core-modules/feature-flag/services/feature-flag.service';
 import { FlatWorkspace } from 'src/engine/core-modules/workspace/types/flat-workspace.type';
-import { DataSourceService } from 'src/engine/metadata-modules/data-source/data-source.service';
 import {
   FlatEntityMapsException,
   FlatEntityMapsExceptionCode,
@@ -37,28 +34,13 @@ export class WorkspaceGraphqlSchemaSDLService {
     private readonly workspaceGraphQLSchemaGenerator: WorkspaceGraphQLSchemaGenerator,
     private readonly workspaceCacheStorageService: WorkspaceCacheStorageService,
     private readonly workspaceManyOrAllFlatEntityMapsCacheService: WorkspaceManyOrAllFlatEntityMapsCacheService,
-    private readonly featureFlagService: FeatureFlagService,
-    private readonly dataSourceService: DataSourceService,
   ) {}
 
   async getOrComputeSchemaSDL(
     workspace: FlatWorkspace,
     applicationId?: string,
   ): Promise<WorkspaceGraphqlSchemaSDLResult | null> {
-    const isDataSourceMigrated = await this.featureFlagService.isFeatureEnabled(
-      FeatureFlagKey.IS_DATASOURCE_MIGRATED,
-      workspace.id,
-    );
-
-    const hasSchema = isDataSourceMigrated
-      ? isNonEmptyString(workspace.databaseSchema)
-      : (
-          await this.dataSourceService.getDataSourcesMetadataFromWorkspaceId(
-            workspace.id,
-          )
-        ).length > 0;
-
-    if (!hasSchema) {
+    if (!isNonEmptyString(workspace.databaseSchema)) {
       return null;
     }