[TYPES] UniversalEntity JsonbProperty and SerializedRelation (#17396)

# Introduction

In this PR we're introducing mainly two branded type signatures for both
`JsonbProperty` entities properties and `SerializedRelation` (jsonb
serialized property storing another entity id).

Allowing to dynamically map over them later in order to build universal
`jsonb` `serialized` relations.

## `JsonbProperty`

A branded wrapper type that marks entity properties stored as PostgreSQL
JSONB columns. It adds a phantom brand `__JsonbPropertyBrand__` to
object types while leaving primitives unchanged. The branded key is
optional and typed as never, also omitted when transpiled to
`UniversalFlat`

**Should be used at entities lvl only:**
```typescript
@Column({ type: 'jsonb', nullable: false })
gridPosition: JsonbProperty<GridPosition>;

@Column({ nullable: false, type: 'jsonb', default: [] })
publishedVersions: JsonbProperty<string[]>;
```

## `SerializedRelation`

A branded string type that marks foreign key IDs stored inside JSONB
objects. These are entity references serialized within a JSONB column
rather than being a regular database foreign key.

**Usage in jsonb property generic***
```ts
type FieldMetadataRelationSettings = {
  relationType: RelationType;
  onDelete?: RelationOnDeleteAction;
  joinColumnName?: string | null;
  junctionTargetFieldId?: SerializedRelation;
};
```

## `FormatJsonbSerializedRelation<T>`

A transformation type that processes JSONB properties for universal
entity mapping. It:
1. Detects properties with the `JsonbProperty` brand
2. Finds `SerializedRelation` properties
3. Renames them from `*Id` to `*UniversalIdentifier`
4. Removes the brand from the output type ( optional though )

```typescript
// Input: JsonbProperty<{ targetFieldMetadataId: SerializedRelation }>
// Output: { targetFieldMetadataUniversalIdentifier: SerializedRelation }
```

## Result
An example of the dynamic type mapping, through a type-test example
```ts
type SettingsTestCase = UniversalFlatFieldMetadata<
    | FieldMetadataType.RELATION
    | FieldMetadataType.NUMBER
    | FieldMetadataType.TEXT
  >['settings']

type SettingsExpectedResult =
  | {
      relationType: RelationType;
      onDelete?: RelationOnDeleteAction | undefined;
      joinColumnName?: string | null | undefined;
      junctionTargetFieldUniversalIdentifier?: SerializedRelation | undefined;
    }
  | {
      dataType?: NumberDataType | undefined;
      decimals?: number | undefined;
      type?: FieldNumberVariant | undefined;
    }
  | {
      displayedMaxRows?: number | undefined;
    }
  | null;

type Assertions = [
  Expect<Equal<SettingsTestCase, SettingsExpectedResult>>,
]
```

## Remarks

- Removed duplicated twenty-server and twenty-shared typed
- Removed class validator instances for default value that were not used
at runtime, we will refactor that to add validation across all entities
following a same pattern

packages/twenty-server/src/engine/metadata-modules/ai/ai-agent/entities/agent.entity.ts

@@ -15,6 +15,7 @@ import {
   ModelId,
 } from 'src/engine/metadata-modules/ai/ai-models/constants/ai-models.const';
 import { SyncableEntity } from 'src/engine/workspace-manager/types/syncable-entity.interface';
+import { JsonbProperty } from 'src/engine/workspace-manager/workspace-migration/universal-flat-entity/types/jsonb-property.type';
 
 @Entity('agent')
 @Index('IDX_AGENT_ID_DELETED_AT', ['id', 'deletedAt'])
@@ -52,7 +53,7 @@ export class AgentEntity
 
   // Should not be nullable
   @Column({ nullable: true, type: 'jsonb', default: { type: 'text' } })
-  responseFormat: AgentResponseFormat;
+  responseFormat: JsonbProperty<AgentResponseFormat>;
 
   @Column({ default: false })
   isCustom: boolean;
@@ -67,7 +68,7 @@ export class AgentEntity
   deletedAt: Date | null;
 
   @Column({ nullable: true, type: 'jsonb' })
-  modelConfiguration: ModelConfiguration | null;
+  modelConfiguration: JsonbProperty<ModelConfiguration> | null;
 
   @Column({ type: 'text', array: true, default: '{}' })
   evaluationInputs: string[];