AgentCore provides no information on AWS account or profile being used

### Description

The AgentCore "getting started" instructions are not clear that "local" development actually accesses AWS, and critically **apparently provides no indication of which AWS account is being used**.

### Steps to Reproduce

Follow the instructions for [Get started with the AgentCore CLI](https://docs.aws.amazon.com/bedrock-agentcore/latest/devguide/runtime-get-started-cli.html):

```bash
agentcore create --name MyAgent --framework Strands --protocol HTTP --model-provider Bedrock --memory none
cd MyAgent
agentcore status
```

Status says:

> AgentCore Status (target: )
>
> Agents
> MyAgent: Local only

Then run:

```bash
agentcore dev
```

Enter a question, e.g.:

> What are the benefits of uv over pip?

### Expected Behavior

1. "Local only" means no server access.
2. If an AWS account is accessed, `agentcore status` should indicate which account is being accessed.

### Actual Behavior

1. An error occurred, which apparently means that "local only" is not "local only".
> Error: An error occurred (AccessDeniedException) when calling the ConverseStream operation: Your account is currently being verified. Verification normally takes less than 2 hours. Until your account is verified, you may not have access to this operation. If you are still receiving this message after more than 2 hours, please let us know by writing to [aws-verification@amazon.com](mailto:aws-verification@amazon.com). We appreciate your patience.
2. There is no information about which AWS account is being accessed, and no obvious way to find out.

### CLI Version

0.27.0

### Operating System

Windows

### Additional Context

AWS best practices requires setting up multiple accounts. Users need to be able to know which account is being accessed. This issue is a compounding of the critical oversight of #1727: the `--profile` switch is not implemented, and it's not even clear if `AWS_PROFILE` is supported. Therefore, when the "local" setup tries to access something that isn't local, users need to know what it's trying to access.

1. Improve the documentation to explain that "local" (apparently) only refers to the agent harness; an AWS account is still being accessed.
2. Implement `--profile` and `AWS_PROFILE` from #1727.
3. Provide visibility in `agentcore status` to indicate which profile is being resolved.

Start with the AgentCore CLI status/dev entry points and the getting-started CLI documentation linked in the issue; review #1727 for profile support context. Done means the docs explain local AWS access and status identifies the resolved account or profile, with behavior checked against the reported Windows flow.

Written by the indexing model from the issue text.