msobczyk/handle signals in docker entrypoint

handle signals in docker entrypoint, handle exit in start_clive script (close container on terminal close), closes issue #274 (closed)

clive/__private/run_tui.py

 from __future__ import annotations
 
+import asyncio
+import signal
 import sys
 import warnings
 
@@ -11,10 +13,24 @@ def _hide_never_awaited_warnings_in_non_dev_mode() -> None:
         warnings.filterwarnings("ignore", message=".* was never awaited")
 
 
+async def _shutdown_gracefully() -> None:
+    from clive.__private.ui.app import Clive
+
+    await Clive.app_instance().action_quit()
+    asyncio.get_event_loop().stop()
+
+
+def _handle_close_signals_in_tui() -> None:
+    loop = asyncio.get_event_loop()
+    for signal_number in [signal.SIGHUP, signal.SIGINT, signal.SIGQUIT, signal.SIGTERM]:
+        loop.add_signal_handler(signal_number, lambda: asyncio.create_task(_shutdown_gracefully()))
+
+
 async def run_tui() -> None:
     from clive.__private.before_launch import prepare_before_launch
     from clive.__private.ui.app import Clive
 
     _hide_never_awaited_warnings_in_non_dev_mode()
+    _handle_close_signals_in_tui()
     prepare_before_launch()
     sys.exit(await Clive.app_instance().run_async())