feat: added ctrl_c from grum

bec_widgets/ctrl_c.py

@@ -0,0 +1,38 @@
+import signal
+import socket
+from PyQt5.QtNetwork import QAbstractSocket
+
+
+def setup(app):
+    app.signalwatchdog = SignalWatchdog()  # need to store to keep socket pair alive
+    signal.signal(signal.SIGINT, make_quit_handler(app))
+
+
+def make_quit_handler(app):
+    def handler(*args):
+        print()  # make ^C appear on its own line
+        app.quit()
+
+    return handler
+
+
+class SignalWatchdog(QAbstractSocket):
+    def __init__(self):
+        """
+        Propagates system signals from Python to QEventLoop
+        adapted from https://stackoverflow.com/a/65802260/655404
+        """
+        super().__init__(QAbstractSocket.SctpSocket, None)
+
+        self.writer, self.reader = writer, reader = socket.socketpair()
+        writer.setblocking(False)
+
+        fd_writer = writer.fileno()
+        fd_reader = reader.fileno()
+
+        signal.set_wakeup_fd(fd_writer)  # Python hook
+        self.setSocketDescriptor(fd_reader)  # Qt hook
+
+        self.readyRead.connect(
+            lambda: None
+        )  # dummy function call that lets the Python interpreter run