Add email thread widget and message thread record page layout (#19351)

## Summary
- Move email thread display from side panel to a dedicated record page
with a new `EMAIL_THREAD` widget type
- Add message thread as a standard object with page layout, subject
field, and backfill command
- Add reply-to-email command menu item for message thread records
- Remove old side panel message thread components in favor of the new
widget-based approach

## Type fixes
- Add `EMAIL_THREAD` to `WidgetConfigurationType`, `WidgetType`, and all
configuration/validator maps
- Create `EmailThreadConfigurationDTO` and shared
`EmailThreadConfiguration` type
- Register EMAIL_THREAD in widget type validators, configuration
resolvers, and standard widget mappings

## Test plan
- [ ] Verify message thread record pages render with the email thread
widget
- [ ] Verify email thread preview navigates to the record page instead
of opening side panel
- [ ] Verify reply-to-email command appears for message thread records
- [ ] Verify typecheck passes for both twenty-front and twenty-server
- [ ] Run existing test suites to check for regressions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/twenty-server/src/modules/messaging/common/standard-objects/message-thread.workspace-entity.ts

@@ -1,7 +1,17 @@
+import { FieldMetadataType } from 'twenty-shared/types';
+
 import { BaseWorkspaceEntity } from 'src/engine/twenty-orm/base.workspace-entity';
+import { type FieldTypeAndNameMetadata } from 'src/engine/workspace-manager/utils/get-ts-vector-column-expression.util';
 import { type EntityRelation } from 'src/engine/workspace-manager/workspace-migration/types/entity-relation.interface';
 import { type MessageWorkspaceEntity } from 'src/modules/messaging/common/standard-objects/message.workspace-entity';
 
+const SUBJECT_FIELD_NAME = 'subject';
+
+export const SEARCH_FIELDS_FOR_MESSAGE_THREAD: FieldTypeAndNameMetadata[] = [
+  { name: SUBJECT_FIELD_NAME, type: FieldMetadataType.TEXT },
+];
+
 export class MessageThreadWorkspaceEntity extends BaseWorkspaceEntity {
+  subject: string | null;
   messages: EntityRelation<MessageWorkspaceEntity[]>;
 }

packages/twenty-server/src/modules/messaging/message-import-manager/services/messaging-message.service.ts

@@ -25,7 +25,7 @@ type MessageAccumulator = {
     | 'text'
     | 'messageThreadId'
   >;
-  threadToCreate?: Pick<MessageThreadWorkspaceEntity, 'id'>;
+  threadToCreate?: Pick<MessageThreadWorkspaceEntity, 'id' | 'subject'>;
   messageChannelMessageAssociationToCreate?: Pick<
     MessageChannelMessageAssociationWorkspaceEntity,
     | 'id'
@@ -199,10 +199,52 @@ export class MessagingMessageService {
           .map((accumulator) => accumulator.threadToCreate)
           .filter(isDefined);
 
-        await messageThreadRepository.insert(
-          messageThreadsToCreate,
-          transactionManager,
-        );
+        const threadSubjectUpdates = new Map<
+          string,
+          { subject: string; receivedAt: number }
+        >();
+
+        for (const message of messages) {
+          const messageAccumulator = messageAccumulatorMap.get(
+            message.externalId,
+          );
+
+          if (!isDefined(messageAccumulator)) {
+            continue;
+          }
+
+          if (
+            isDefined(messageAccumulator.existingThreadInDB) &&
+            isDefined(messageAccumulator.messageToCreate) &&
+            isDefined(message.subject)
+          ) {
+            const threadId = messageAccumulator.existingThreadInDB.id;
+            const existing = threadSubjectUpdates.get(threadId);
+            const receivedAt = message.receivedAt?.getTime() ?? 0;
+
+            if (!isDefined(existing) || receivedAt > existing.receivedAt) {
+              threadSubjectUpdates.set(threadId, {
+                subject: message.subject,
+                receivedAt,
+              });
+            }
+          }
+        }
+
+        const threadsToUpsert = [
+          ...messageThreadsToCreate,
+          ...Array.from(threadSubjectUpdates.entries()).map(
+            ([id, { subject }]) => ({ id, subject }),
+          ),
+        ];
+
+        if (threadsToUpsert.length > 0) {
+          await messageThreadRepository.upsert(
+            threadsToUpsert,
+            ['id'],
+            transactionManager,
+          );
+        }
 
         const messagesToCreate = Array.from(messageAccumulatorMap.values())
           .map((accumulator) => accumulator.messageToCreate)
@@ -451,6 +493,7 @@ export class MessagingMessageService {
 
         messageAccumulator.threadToCreate = {
           id: newOrExistingMessageThreadId,
+          subject: message.subject,
         };
       }