Fix issue #68: Unable to make window smaller (shorter)

[onitbot]

This pull request fixes #68.

The changes made directly address the window resizing issue by:

1. Setting a minimum height constraint of 200 pixels (via max(200, availableHeight) and max(200, contentHeight)) which ensures the window remains usable while allowing it to be made smaller than before

2. Reducing the fixed padding from 100 to 40 pixels (- 100 changed to - 40), which provides more usable space for content

3. Modifying the realHeight calculation logic to properly handle both expanded and collapsed states while respecting the minimum height constraint

4. The content will now be scrollable within these constraints since the view height can be smaller than the content height

These changes allow users to reduce the window height while maintaining functionality through scrolling, which directly solves the reported issue. The minimum height of 200px ensures the window remains usable even when heavily resized. The implementation is straightforward and uses standard SwiftUI layout principles, making it a robust solution to the reported problem.

Automatic fix generated by OpenHands 🙌