bug(tui): supervised workflow TUI Logs tab shows no output #16

Problem

In supervised workflow runs (Supervisor -> Core IPC -> Worker) with the TUI enabled, the 2: Logs tab does not show real-time worker output (stdout/stderr/progress/patch).

Steps to Reproduce

• Run: roboppi workflow examples/hello-world.yaml --supervised --tui
• Switch to 2: Logs

Expected

Real-time worker output is visible while the step is executing.

Actual

Logs remain empty (often shows "No logs yet").

Fix

Implemented in PR #15.

Notes

• Opt-out stdout/stderr forwarding with ROBOPPI_TUI_STREAM_STDIO=0 (progress/patch continue to stream).