Documentation needs to add CLI based cleanup in 01-features/01-harness/00-getting-started - [Content Improvement]

**Please list the sample in which the bug is present.**

```
01-features/01-harness/00-getting-started/README.md
```

**Improvement Description**
Documentation needs to add CLI based cleanup in 01-features/01-harness/00-getting-started/README.md file.

There is no CLI based cleanup command provided. Need to give the command for the users who used interactive mode to run the harness.

We need to tell the users to execute the CLI as:

> From the same AgentCore project directory where you originally ran agentcore deploy:

`agentcore remove all`

Then:

`agentcore deploy`

or better:

Preview the removal:

`agentcore remove all --dry-run`

Then, if the output looks correct:

```bash
agentcore remove all
agentcore deploy
```

Finally:
`agentcore status`

Source: CLI command:

```bash
agentcore remove all --help
Usage: agentcore remove all [options]

Reset all agentcore schemas to empty state

Options:
-y, --yes Skip confirmation prompts [non-interactive]
--dry-run Show what would be reset without actually resetting [non-interactive]
--json Output as JSON [non-interactive]
-h, --help Display help
```