Python: Harness console for python (#6312)

* Add initial harness console for python

* Add textual to project

* Add planning and approval flows with list selector

* Address PR comments

* Fix list selection bug

* Fix PR #6312 round 2 review comments

- Escape untrusted agent text with rich.markup.escape() in observers
  (text_output, planning_output, reasoning_display) to prevent markup injection
- Remove non-functional 'Always approve' choices from tool_approval.py
  (framework lacks CreateAlwaysApproveToolResponse support)
- Remove textual from root pyproject.toml dev deps (sample-specific)
- Add PEP 723 inline script metadata to harness_research.py
- Narrow except Exception to except NoMatches in list_selection.py

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix build error

* Fix build errors

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

python/samples/02-agents/harness/console/commands/mode_handler.py

@@ -0,0 +1,81 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Mode command handler — /mode to show or switch agent mode."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from .base import CommandHandler
+
+if TYPE_CHECKING:
+    from agent_framework import AgentModeProvider, AgentSession
+
+    from ..state_driver import IUXStateDriver
+
+
+class ModeCommandHandler(CommandHandler):
+    """Handle the /mode command to display or switch the current agent mode."""
+
+    def __init__(
+        self,
+        mode_provider: AgentModeProvider | None,
+        mode_colors: dict[str, str] | None = None,
+    ) -> None:
+        """Initialize with mode provider and color mapping.
+
+        Args:
+            mode_provider: The mode provider, or None if not available.
+            mode_colors: Optional mapping of mode names to Rich color strings.
+        """
+        self._mode_provider = mode_provider
+        self._mode_colors = mode_colors or {}
+
+    def get_help_text(self) -> str | None:
+        """Return help text, or None if mode provider is unavailable."""
+        if self._mode_provider is None:
+            return None
+        return "/mode [plan|execute] (show or switch mode)"
+
+    async def try_handle(
+        self,
+        user_input: str,
+        session: AgentSession,
+        ux: IUXStateDriver,
+    ) -> bool:
+        """Handle /mode [name] command."""
+        stripped = user_input.strip()
+        lower = stripped.lower()
+
+        if not (lower == "/mode" or lower.startswith("/mode ")):
+            return False
+
+        if self._mode_provider is None:
+            ux.append_info_line("AgentModeProvider is not available.")
+            return True
+
+        parts = stripped.split(None, 1)
+        if len(parts) < 2:
+            # Show current mode
+            from agent_framework import get_agent_mode
+
+            current = get_agent_mode(session)
+            ux.append_info_line(f"Current mode: {current}")
+            return True
+
+        # Switch mode
+        new_mode = parts[1].strip()
+        try:
+            from agent_framework import set_agent_mode
+
+            normalized = set_agent_mode(session, new_mode)
+            color = self._mode_colors.get(normalized)
+            ux.set_mode(normalized, color)
+            ux.append_info_line(
+                f"Switched to {normalized} mode.",
+                color=color,
+            )
+        except ValueError as ex:
+            ux.append_info_line(str(ex), color="red")
+
+        return True