[FEATURE]: Web UI does not show shell command or output while a shell is running

[HopelessLoop]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Related: #22116 ("[BUG] Web UI hides bash output during execution despite streaming data being available") — closed as "not planned", no fix merged. Reopening the same problem.

Description:
In the web UI, when a shell command is executed (shell mode or /shell), only the "Shell" header with a loading spinner is shown. The command being run and its output are not visible, and there is no expand control during execution. The TUI shows the command and the live output inline while the shell runs. After the command finishes, the web UI shows a collapsed tool that can be expanded to view the command and result.

Steps to reproduce:

1. Open the web UI.
2. Switch to shell mode (or run /shell) and execute a command.
3. While it runs, observe that only "Shell" + spinner appears — the command and output are hidden.

Expected behavior:
Match the TUI: show the command and the live output inline while the shell is running.

Environment:

• OS: Linux
• Terminal: browser
• OpenCode version: v1.18.x