Refactor entity handling to preserve config while overriding type

Reworked `ensureEntity` to replace entities while maintaining their configuration and allowing type adjustments. Updated tests to verify type persistence and synchronization of entity properties.

app/src/data/entities/Entity.ts

@@ -140,7 +140,7 @@ export class Entity<
       return this.fields.find((field) => field.name === name);
    }
 
-   __experimental_replaceField(name: string, field: Field) {
+   __replaceField(name: string, field: Field) {
       const index = this.fields.findIndex((f) => f.name === name);
       if (index === -1) {
          throw new Error(`Field "${name}" not found on entity "${this.name}"`);

app/src/data/entities/EntityManager.ts

@@ -99,6 +99,16 @@ export class EntityManager<TBD extends object = DefaultDB> {
       this.entities.push(entity);
    }
 
+   __replaceEntity(entity: Entity, name: string | undefined = entity.name) {
+      const entityIndex = this._entities.findIndex((e) => e.name === name);
+
+      if (entityIndex === -1) {
+         throw new Error(`Entity "${name}" not found and cannot be replaced`);
+      }
+
+      this._entities[entityIndex] = entity;
+   }
+
    entity(e: Entity | keyof TBD | string): Entity {
       let entity: Entity | undefined;
       if (typeof e === "string") {