Merge origin/main into feat/show-reasoning

Resolves conflicts after main landed the state-machine turn refactor
and the test_runner.py 9-file split:

- nanobot/agent/loop.py: take main's `_state_build`/`_persist_user_message_early`
  flow; restore the `reasoning: bool` parameter on `_build_bus_progress_callback`
  so the loop hook can mark progress as reasoning-channel without coupling to
  the answer stream.
- nanobot/cli/stream.py: keep main's configurable `bot_name`/`bot_icon` header
  while preserving the PR's `transient=True` Live + `self._console` routing
  + `_renderable()` final-render path that fixed TUI duplication.
- tests/agent/test_runner.py was deleted on main and split into 9 focused
  files; relocated all 6 reasoning tests into a new `test_runner_reasoning.py`
  matching the new layout, deduplicated the per-test `ReasoningHook` boilerplate
  through a shared `_RecordingHook` helper.

Co-authored-by: Cursor <cursoragent@cursor.com>

nanobot/utils/helpers.py

@@ -252,11 +252,6 @@ def find_legal_message_start(messages: list[dict[str, Any]]) -> int:
             if tid and str(tid) not in declared:
                 start = i + 1
                 declared.clear()
-                for prev in messages[start : i + 1]:
-                    if prev.get("role") == "assistant":
-                        for tc in prev.get("tool_calls") or []:
-                            if isinstance(tc, dict) and tc.get("id"):
-                                declared.add(str(tc["id"]))
     return start