Enable SSH Access to Computing Units

### Feature Summary

Enable users to access a terminal/shell interface for their Computing Units (CUs) through the web interface. This feature provides SSH-like access to CUs, allowing users to interact with the execution environment directly via a web-based terminal.

### Proposed Solution or Design

Implement web-based terminal access to Computing Units using ttyd (terminal over HTTP/WebSocket) with the following components:

#### Architecture Changes
Before the change, each CU contains one process: the amber process:

After the change, each CU contains two processes: the amber process & the SSH service process

Here is the network traffic when users want to connect to CU through the browser:

### Impact / Priority

(P2)Medium – useful enhancement

### Affected Area

Other