UI: Extraneous empty lines in history output

[jwhelangoog]

What happened?

Extraneous empty lines are being written to the history output in the terminal UI. This is particularly noticeable around tool execution outputs. The logic for top margins and borders is creating unintended gaps in the output stream.

What did you expect to happen?

The history output should be visually dense and cohesive, without unnecessary vertical whitespace or empty lines between contiguous history items and tool groups.

Client information

Client Information

Platform: macOS (darwin)

Anything else we need to know?

PR is currently being drafted to address the layout issues.

[jwhelangoog]

Confirm message types look correct across each combination of settings:

• Topic & Update Narrations: true/false
• Compact Tool Output: true/false

[jwhelangoog]

screencast showing changes: http://screencast/cast/NTM5NzQxMzc1MjczMzY5NnxiYzdkODQxYy1mYg

(noticeable changes begin about 20s in)