[Docs]: Default setup should use plain Claude Code; Bedrock configuration should be optional

### Version

v2 (alpha)

### Type of Documentation Problem

Unclear or confusing explanation

### Location

1. README.md
Claude Code -> 1. Install Claude Code

2. settings.json
https://github.com/awslabs/aidlc-workflows/blob/v2/dist/claude/.claude/settings.json#L22-L30

### Description

The Claude Code setup in the README defaults to using Amazon Bedrock, and settings.json is also configured with the assumption that Bedrock is being used.

Since some people use Claude Code as-is (without Bedrock), I encountered an issue where Claude Code does not work properly because Bedrock settings are included from the start.

```
/aidlc --doctor

✻ API error · Retrying in 0s · attempt 4/10
⎿ Tip: Use /btw to ask a quick side question without interrupting Claude's current work
```

### Suggested Fix

I think it would be more user-friendly to make the default assumption plain Claude Code, and move the Bedrock configuration into an optional/separate instruction guide.

Start with the Claude Code installation section in README.md and the Bedrock-related settings in dist/claude/.claude/settings.json, especially lines 22-30. Make the default setup use plain Claude Code and move Bedrock configuration into separate optional instructions; verify that the documented default no longer assumes Bedrock.

Written by the indexing model from the issue text.