TUI change panel shows only file operations, not actual diffs

Description

In the TUI, when the agent modifies files, the change view lists only operations (e.g. edited / created / deleted badges per file) rather than the actual line-level diff of what changed. This makes it hard to review what the agent actually did to each file.

I tried both diff_style: "auto" and "stacked" in tui.json; neither shows the per-file diff content — only the operation list.

Steps to reproduce

1. Run opencode in a git repo.
2. Ask it to edit a file.
3. Inspect the change panel for the edited file.

Expected

The change panel shows the actual line-by-line diff (old vs new content) for each changed file.

Actual

Only a record of operations (e.g. "edited file X") is shown, with no content comparison.

Environment

• OS: Windows
• Version: latest opencode TUI