Migrate view filter group to v2 (#16876)

## Introduction
On the side hanlded PR with a // agents on another repo
Made several iterations to fix behavior and direction
Find below auto-generated PR description

closes https://github.com/twentyhq/core-team-issues/issues/2037

Created generic tooling for entity circular dep checking, will be useful
for permissions validation too @Weiko


## Migrate `viewFilterGroup` entity to v2 flat architecture

### Summary
Migrates the `viewFilterGroup` entity from v1 to the v2 flat entity
architecture, following the established patterns for other v2 entities
like `viewFilter`, `view`, and `viewField`.

### Changes

**Types & Constants**
- Added `FlatViewFilterGroup` and `FlatViewFilterGroupMaps` types
- Added editable properties constant for `viewFilterGroup`
- Registered `viewFilterGroup` in `ALL_METADATA_NAME`,
`ALL_METADATA_RELATION_PROPERTIES`,
`ALL_METADATA_MANY_TO_ONE_RELATIONS`, and related constants

**Cache Service**
- Created `WorkspaceFlatViewFilterGroupMapCacheService` with proper
relation loading for `viewFilters` and `childViewFilterGroups`
- Updated `WorkspaceFlatViewMapCacheService` to load `viewFilterGroups`
relation

**Builder & Validator**
- Created `WorkspaceMigrationV2ViewFilterGroupActionsBuilderService`
- Created `FlatViewFilterGroupValidatorService` with creation, update,
and deletion validation
- Integrated validation into the orchestrator service (runs before
`viewFilter` validation)

**Action Handlers**
- Created create, update, and delete action handlers for
`viewFilterGroup`

**Service Migration**
- Rewrote `ViewFilterGroupService` to use v2 migration pattern with
`WorkspaceMigrationValidateBuildAndRunService`
- Created utility functions for transforming DTOs to flat entities

**Database Migration**
- Added migration to make `parentViewFilterGroupId` foreign key
deferrable (handles self-referential parent/child insertions)

**ViewFilter Integration**
- Added `viewFilterGroupId` validation in
`FlatViewFilterValidatorService`
- Updated `viewFilter` many-to-one relations to include
`viewFilterGroup`

**Tests**
- Added integration tests for successful creation, update, deletion, and
destruction
- Added failing test cases for non-existent entities and invalid
references
- Added failing test for `viewFilter` creation with non-existent
`viewFilterGroupId`

### Breaking Changes
None - existing API contracts are preserved.

packages/twenty-server/src/engine/metadata-modules/flat-view/flat-view.module.ts

@@ -3,6 +3,7 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 
 import { WorkspaceFlatViewMapCacheService } from 'src/engine/metadata-modules/flat-view/services/workspace-flat-view-map-cache.service';
 import { ViewFieldEntity } from 'src/engine/metadata-modules/view-field/entities/view-field.entity';
+import { ViewFilterGroupEntity } from 'src/engine/metadata-modules/view-filter-group/entities/view-filter-group.entity';
 import { ViewFilterEntity } from 'src/engine/metadata-modules/view-filter/entities/view-filter.entity';
 import { ViewGroupEntity } from 'src/engine/metadata-modules/view-group/entities/view-group.entity';
 import { ViewEntity } from 'src/engine/metadata-modules/view/entities/view.entity';
@@ -14,6 +15,7 @@ import { ViewEntity } from 'src/engine/metadata-modules/view/entities/view.entit
       ViewFieldEntity,
       ViewFilterEntity,
       ViewGroupEntity,
+      ViewFilterGroupEntity,
     ]),
   ],
   providers: [WorkspaceFlatViewMapCacheService],