[FEATURE] Feature request: Resizable & vertical split view panels in desktop app

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

When using multiple sessions in split view (e.g., 3-4 panels), all panels are equally sized and cannot be resized individually. Hovering over panel borders does not show a resize cursor. Also, 3 sessions are displayed in a 2+1 grid layout with no option to arrange them as 3 vertical columns.

Proposed Solution

Resizable panels: Allow users to drag the divider between panels to resize each session's width/height, similar to how most IDEs (VS Code, JetBrains) handle split views.

Vertical 3-column split: Support a side-by-side 3-column layout (left | center | right) in addition to the current grid layout, for better readability when comparing or referencing multiple sessions simultaneously.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Interactive mode (TUI)

Use Case Example

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Additional Context

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