feat: emit metadata events for schema changes with actor context for webhooks (#17622)

## Summary

This PR adds **metadata eventing**: when schema metadata
(objectMetadata, fieldMetadata, view, viewField, etc.) is created,
updated, or deleted, we now emit events that can trigger webhooks and
future audit logs. It also adds **actor context** (`userId`,
`workspaceMemberId`) to those events so subscribers can attribute
changes to a user or API key.

## What changed

### 1. Metadata eventing (first commit)

- **MetadataEventEmitter**  
New service that emits batch events after successful workspace
migrations. Event names follow `metadata.{entity}.{action}` (e.g.
`metadata.objectMetadata.created`, `metadata.fieldMetadata.updated`).
- **MetadataEventsToDbListener**  
Listens for metadata events and enqueues webhook delivery via
`CallWebhookJobsForMetadataJob`.
- **Event types** (twenty-shared)  
`MetadataEventAction`, `MetadataEventBatch`, and record event types for
create/update/delete.
- **WorkspaceMigrationValidateBuildAndRunService**  
Calls the metadata event emitter after running migrations so all
metadata changes (from any module) emit events from a single place.
- **Create events**  
Sourced from the create action payload (`flatEntity` /
`flatFieldMetadatas`) because `fromToAllFlatEntityMaps` does not provide
a before/after diff for creates. Update/delete events still use the
fromToAllFlatEntityMaps comparison.

### 2. Actor context (second commit)

- **MetadataEventEmitter**  
Accepts optional `actorContext` (`userId`, `workspaceMemberId`) and
includes it on emitted batch events.
- **WorkspaceMigrationValidateBuildAndRunService**  
Passes `actorContext` from the request into the metadata event emitter.
- **Metadata resolvers & services**  
All metadata modules resolve `@AuthUser({ allowUndefined: true })` and
`@AuthUserWorkspaceId()` and pass `userId` and `workspaceMemberId`
through to the migration/event pipeline. Both are optional so
API-key–authenticated requests (no user) still emit events without a
user identity.
  
Shared some questions on Discord about the PR.

---------

Co-authored-by: Félix Malfait <felix.malfait@gmail.com>
Co-authored-by: prastoin <paul@twenty.com>

packages/twenty-server/src/engine/workspace-manager/workspace-migration/services/workspace-migration-validate-build-and-run-service.ts

@@ -7,6 +7,7 @@ import {
 import { isDefined } from 'twenty-shared/utils';
 
 import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
+import { MetadataEventEmitter } from 'src/engine/metadata-event-emitter/metadata-event-emitter';
 import { ALL_METADATA_REQUIRED_METADATA_FOR_VALIDATION } from 'src/engine/metadata-modules/flat-entity/constant/all-metadata-required-metadata-for-validation.constant';
 import { createEmptyFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/constant/create-empty-flat-entity-maps.constant';
 import { AllFlatEntityMaps } from 'src/engine/metadata-modules/flat-entity/types/all-flat-entity-maps.type';
@@ -53,6 +54,7 @@ export class WorkspaceMigrationValidateBuildAndRunService {
     private readonly workspaceMigrationRunnerService: WorkspaceMigrationRunnerService,
     private readonly workspaceMigrationBuildOrchestratorService: WorkspaceMigrationBuildOrchestratorService,
     private readonly workspaceCacheService: WorkspaceCacheService,
+    private readonly metadataEventEmitter: MetadataEventEmitter,
     twentyConfigService: TwentyConfigService,
   ) {
     const logLevels = twentyConfigService.get('LOG_LEVELS');
@@ -248,7 +250,13 @@ export class WorkspaceMigrationValidateBuildAndRunService {
         })
       : validateAndBuildResult.workspaceMigration;
 
-    await this.workspaceMigrationRunnerService.run(workspaceMigration);
+    const { metadataEvents } =
+      await this.workspaceMigrationRunnerService.run(workspaceMigration);
+
+    this.metadataEventEmitter.emitMetadataEvents({
+      metadataEvents,
+      workspaceId: args.workspaceId,
+    });
   }
 
   public async validateBuildAndRunWorkspaceMigration({