feat(cli): display model reasoning content during streaming

Add show_reasoning config (default: False) to display model
thinking/reasoning content in the TUI during streaming.  Reasoning
is emitted via a new emit_reasoning hook on AgentHook, gated by the
channels config.  Display uses ✻ prefix with dim italic styling.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/cli/test_interactive_retry_wait.py

@@ -29,3 +29,62 @@ async def test_interactive_retry_wait_is_rendered_as_progress_even_when_progress
 
     assert handled is True
     assert calls == [("Model request failed, retry in 2s (attempt 1).", thinking)]
+
+
+@pytest.mark.asyncio
+async def test_reasoning_displayed_when_show_reasoning_enabled():
+    """Reasoning content should be displayed when show_reasoning is True."""
+    calls: list[str] = []
+    channels_config = SimpleNamespace(
+        send_progress=True, send_tool_hints=False, show_reasoning=True,
+    )
+    msg = SimpleNamespace(
+        content="Let me think about this...",
+        metadata={"_progress": True, "_reasoning": True},
+    )
+
+    with patch("nanobot.cli.commands._print_cli_reasoning", side_effect=lambda t, th, r=None: calls.append(t)):
+        handled = await commands._maybe_print_interactive_progress(msg, None, channels_config)
+
+    assert handled is True
+    assert calls == ["Let me think about this..."]
+
+
+@pytest.mark.asyncio
+async def test_reasoning_hidden_when_show_reasoning_disabled():
+    """Reasoning content should be suppressed when show_reasoning is False."""
+    channels_config = SimpleNamespace(
+        send_progress=True, send_tool_hints=False, show_reasoning=False,
+    )
+    msg = SimpleNamespace(
+        content="Let me think about this...",
+        metadata={"_progress": True, "_reasoning": True},
+    )
+
+    with patch("nanobot.cli.commands._print_cli_reasoning") as mock_reasoning:
+        handled = await commands._maybe_print_interactive_progress(msg, None, channels_config)
+
+    assert handled is True
+    mock_reasoning.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_non_reasoning_progress_not_affected_by_show_reasoning():
+    """Regular progress lines should display regardless of show_reasoning."""
+    calls: list[str] = []
+    channels_config = SimpleNamespace(
+        send_progress=True, send_tool_hints=False, show_reasoning=False,
+    )
+    msg = SimpleNamespace(
+        content="working on it...",
+        metadata={"_progress": True},
+    )
+
+    async def fake_print(text: str, thinking=None, renderer=None):
+        calls.append(text)
+
+    with patch("nanobot.cli.commands._print_interactive_progress_line", side_effect=fake_print):
+        handled = await commands._maybe_print_interactive_progress(msg, None, channels_config)
+
+    assert handled is True
+    assert calls == ["working on it..."]