[Bug]: Thread timeline and composer are not centered in the free space beside the sidebar and top-right popover #29081

Area: apps/web (desktop app, thread view)
Impact: Cosmetic issue
Environment: macOS, T3 Code Nightly 0.1.7-nightly.20261102.4061

Summary

When the thread details panel ([data-thread-details-panel], the card at the top right with the environment name, "Open in Finder", "Add project script", "Initialize Git" and "Previous agents") is open, the message timeline and the composer stay centered in the full chat column. The panel is absolutely positioned over the column's right side, so the content sits next to the panel instead of in the middle of the free space between the left sidebar and the panel.

Before / after

Before (current)	After (local CSS patch)

Contents are blurred for privacy. The red arrows in the before shot mark the free space the content should be centered in.

Steps to reproduce

1. Open the desktop app with the left sidebar expanded and a thread open.
2. Open the thread details panel at the top right of the thread header.
3. Compare the gap between the sidebar and the timeline with the gap between the timeline and the panel.

Expected behavior

The timeline and the composer are centered horizontally in the free space between the sidebar's right edge and the panel's left edge. When the panel is closed, they center in the full chat column as today.

Actual behavior

Both stay centered in the full chat column. In a 1675px-wide window, the content center is at x=983 while the free space center is at x=894, so the content sits about 90px too far right and ends right beside the panel.

Workaround

This CSS, injected locally, gives the "after" result. It is a sketch, not a proposed fix; the offset should be derived from the panel width rather than hard-coded:

[data-chat-column]:has([data-thread-details-panel])
  :is(.legend-list-content-container, [data-chat-composer-stack]) {
  translate: -90px 0;
}