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/exit_handler.py

@@ -0,0 +1,35 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Exit command handler — /exit to quit the console."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from .base import CommandHandler
+
+if TYPE_CHECKING:
+    from agent_framework import AgentSession
+
+    from ..state_driver import IUXStateDriver
+
+
+class ExitCommandHandler(CommandHandler):
+    """Handle the /exit command to shut down the console application."""
+
+    def get_help_text(self) -> str | None:
+        """Return help text for the exit command."""
+        return "/exit (quit)"
+
+    async def try_handle(
+        self,
+        user_input: str,
+        session: AgentSession,
+        ux: IUXStateDriver,
+    ) -> bool:
+        """Handle /exit by requesting shutdown."""
+        if user_input.strip().lower() != "/exit":
+            return False
+
+        ux.request_shutdown()
+        return True