Typescript support

### Describe the feature

Hello, I would like to contribute a Typescript implementation for programmatic access, based on this class:
https://github.com/awslabs/run-model-context-protocol-servers-with-aws-lambda/blob/main/src/typescript/src/client/streamableHttpWithSigV4.ts

### Use Case

The Typescript MCP SDK is fairly popular

### Proposed Solution

I'd like to first discuss in this issue what layout you prefer for the repo, with implementations for 2 languages Python and Typescript. Some initial ideas below, happy to hear others

### Option 1: Separate directories per language
Move the existing code into a python dir, so the layout would be:
```
typescript/
python/
```

### Option 2: New sub-dir for Typescript impl
Create a new sub-dir like `mcp_proxy_for_aws_ts`, and exclude it from the Python build
```
examples/
mcp_proxy_for_aws/
mcp_proxy_for_aws_ts/
tests/
```

### Option 3: Separate repo for Typescript impl
Create https://github.com/aws/mcp-proxy-for-aws-ts

### Other Information

_No response_

### Acknowledgements

- [x] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

Start by reviewing the referenced streamableHttpWithSigV4.ts implementation and the repository's existing Python layout. The issue's main unresolved task is to agree on whether TypeScript belongs in separate language directories, a new subdirectory, or a separate repository; done means the layout and implementation scope are decided.

Written by the indexing model from the issue text.