[Bug] Web UI chat stream timeline corrupted after native harness shell exec via bang (!)

Description

When using the claude-native harness, running a bash execution via the web composer (e.g., ! env) after a standard text turn (e.g., test) corrupts the chat (abstracted) view

1. Prior response disappears from its own turn (the assistant's response to test is swallowed into the subsequent turn and hidden inside a collapsed "Worked for Xs" section.)
2. Bash output renders before the prompt (the executed command and its stdout appear above the ! env bubble.)
3. The ! env prompt bubble remains stuck at the very bottom of the conversation feed.

Steps to reproduce

1. Launch a session with claude
2. Prompt test
3. Observe response
4. Prompt ! env
5. Observe previous response replaced, and stream corrupted (! env is after the output)

Version

omnigent 0.14.0 (built 2026-09-15T12:56:13Z)

OS

macOS (but same issue on Linux)

Harness

Claude

Harness mode

Native

Platform or device

macOS

Observed impact

All users or sessions

Authentication type

Local