[FEATURE] Interactive mode support for "--system-prompt-file"

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The --system-prompt-file only support print mode, this blocks us from loading system prompt in the file under interactive mode.

https://code.claude.com/docs/en/cli-reference#cli-flags

Proposed Solution

Support --system-prompt-file under interactive mode.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_