feat: migrate ConnectedAccount infrastructure entities to metadata schema (#18784)

## Summary

- Migrates 4 entities (`connectedAccount`, `messageChannel`,
`calendarChannel`, `messageFolder`) from per-workspace schemas to the
shared `core` metadata schema
- Introduces a `IS_CONNECTED_ACCOUNT_MIGRATED` feature flag to control
the migration: when enabled, reads come from core metadata and all
writes are dual-written to both workspace and core
- Extracts 12 enums from workspace entity files to `twenty-shared` for
reuse across frontend and backend
- Creates new TypeORM entities, metadata services, GraphQL
resolvers/DTOs, and exception interceptors per entity
- Each entity owns its own data access module
(`ConnectedAccountDataAccessModule`, `MessageChannelDataAccessModule`,
`CalendarChannelDataAccessModule`, `MessageFolderDataAccessModule`) — no
umbrella infrastructure module
- Adds a 1.20 upgrade command that backfills data from workspace schemas
to core (preserving UUIDs) and enables the feature flag
- Replaces direct repository access with data access service calls
across ~50 files in messaging, calendar, and connected-account modules
- Adds `lastSignedInAt` and `oidcTokenClaims` fields to the new
`ConnectedAccountEntity`
- Drops unused `lastSyncHistoryId` field from the migrated connected
account entity

## Test plan

- [x] Lint passes (`npx nx lint:diff-with-main twenty-server`)
- [x] Typecheck passes (`npx nx typecheck twenty-server`)
- [x] All unit tests pass (477 suites, 4267 tests, 0 failures)
- [ ] Manual test: verify messaging sync works with feature flag
disabled (existing behavior)
- [ ] Manual test: run upgrade command on a workspace, verify data
backfilled to core tables
- [ ] Manual test: verify messaging/calendar sync works with feature
flag enabled (dual-write path)
- [ ] Manual test: verify GraphQL metadata resolvers return correct data
when flag enabled

packages/twenty-server/src/engine/metadata-modules/message-folder/message-folder.exception.ts

@@ -0,0 +1,37 @@
+import { type MessageDescriptor } from '@lingui/core';
+import { msg } from '@lingui/core/macro';
+import { assertUnreachable } from 'twenty-shared/utils';
+
+import { CustomException } from 'src/utils/custom-exception';
+
+export enum MessageFolderExceptionCode {
+  MESSAGE_FOLDER_NOT_FOUND = 'MESSAGE_FOLDER_NOT_FOUND',
+  INVALID_MESSAGE_FOLDER_INPUT = 'INVALID_MESSAGE_FOLDER_INPUT',
+}
+
+const getMessageFolderExceptionUserFriendlyMessage = (
+  code: MessageFolderExceptionCode,
+) => {
+  switch (code) {
+    case MessageFolderExceptionCode.MESSAGE_FOLDER_NOT_FOUND:
+      return msg`Message folder not found.`;
+    case MessageFolderExceptionCode.INVALID_MESSAGE_FOLDER_INPUT:
+      return msg`Invalid message folder input.`;
+    default:
+      assertUnreachable(code);
+  }
+};
+
+export class MessageFolderException extends CustomException<MessageFolderExceptionCode> {
+  constructor(
+    message: string,
+    code: MessageFolderExceptionCode,
+    { userFriendlyMessage }: { userFriendlyMessage?: MessageDescriptor } = {},
+  ) {
+    super(message, code, {
+      userFriendlyMessage:
+        userFriendlyMessage ??
+        getMessageFolderExceptionUserFriendlyMessage(code),
+    });
+  }
+}