Chat timeline content overlaps (assistant text + tool call cards stack on top of each other)

[anghelmatei]

Description

In the chat timeline UI, message content appears to render on top of other blocks instead of flowing vertically.
From the screenshot, assistant text and the TOOL CALLS section overlap, making the conversation hard to read and interact with.

Steps to Reproduce

1. Open T3 Code app.
2. Run a conversation that triggers multiple assistant updates and tool call entries.
3. Scroll in the chat timeline where assistant content and tool-call cards are mixed.
4. Observe layout behavior around the assistant message/tool calls block.

Actual Behavior

• Timeline rows overlap vertically.
• Assistant text appears inside/over other message containers.
• TOOL CALLS cards and nearby message content are visually stacked in the same vertical space.

Expected Behavior

• Each timeline item should reserve its own height.
• Assistant text, tool-call cards, and metadata should be laid out in separate non-overlapping rows.
• Scrolling should preserve readable spacing between items.

Impact

High UX impact: core conversation view becomes difficult to read during normal agent runs with tool calls.

[huxcrux]

I can confirm this happens in like 1/3 threads for me on version 0.0.11 (macos).

I'll try debugging this to find the root cause and hopefully as fix

[huxcrux]

I opened PR #1054 to address this behavior.