import-agent: Specify Bedrock AgentCore Gateway Targets

**Is your feature request related to a problem? Please describe.**

I'm attempting to use the **import-agent** tool to migrate a Bedrock Agent into AgentCore but I'm running into the following issue:

When I try to import a Bedrock Agent that has OpenAPI action group schemas, the import fails with validation errors. It looks like the tool is converting these to Gateway Lambda targets, which only support a limited schema format (type, properties, required, items, description). I can see that AgentCore Gateway supports OpenAPI targets with full schemas, so is this just a current limitation of the tool?

**Describe the solution you'd like**

The ability to specify an AgentCore Gateway target type, such as OpenAI schema, when configuring the migration of an agent using **import-agent**

**Describe alternatives you've considered**
The only alternative I can see is manually migrating the agent.

**Additional context**
Add any other context or screenshots about the feature request here.

Comienza en el punto de entrada de import-agent y sigue cómo los esquemas de grupos de acciones de OpenAPI se convierten en destinos de Gateway Lambda. Compara ese comportamiento con los destinos de OpenAPI de AgentCore Gateway y determina cómo debería representarse un tipo de destino configurable; se considera terminado cuando las importaciones pueden seleccionar un destino compatible con OpenAPI sin los errores de validación actuales.

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