[FEATURE] Make the inline bash output preview height configurable

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

Often the line that matters (final status, error summary) sits just past the cutoff, and bumping the preview by 1-2 lines would make it visible without leaving the inline view.

Proposed Solution

The collapsed bash output box under Bash tool calls shows a fixed number of preview lines. It would help to expose a setting (e.g. bashPreviewLines in settings.json, or a /config toggle) so users can show one or two more lines without having to open the Ctrl+O transcript viewer.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

Configuration and settings

Use Case Example

I'm working with an output that refreshes regularly, and it's 11 lines long. The first line is important (as all 11 lines), and the first line is cut off.

Additional Context

_No response_