After the assistant message is persisted, when tool_uses is empty,
check for inline ```repl blocks and execute them via PythonRuntime:
- Extract REPL blocks from assistant text
- Spawn PythonRuntime and execute each block sequentially
- If a round returns FINAL: replace the assistant message text with
the final value and break the turn
- If no FINAL: append truncated stdout/stderr as user feedback and
continue the turn loop for iterative refinement
- Emit status events so the user sees 'REPL round N: ...' in the UI
All 26 REPL tests + RLM tests pass. Release build verified.
Refs: paper-spec RLM (Zhang et al., arXiv:2512.24601) §2
Hunter Bown
4e46fd06f6