added gui

gui/main.py

@@ -0,0 +1,51 @@
+import sys, os
+
+# Path setup — works both as `python gui/main.py` and `python -m gui.main`
+for _p in [
+    os.path.dirname(os.path.dirname(os.path.abspath(__file__))),  # nmea_client/
+    os.path.dirname(os.path.abspath(__file__)),                   # nmea_client/gui/
+]:
+    if _p not in sys.path:
+        sys.path.insert(0, _p)
+
+from PyQt5.QtWidgets import QApplication, QMainWindow, QTabWidget
+from PyQt5.QtGui     import QIcon
+
+from data_model      import ReceiverManager
+from connection_tab  import ConnectionTab
+from sky_tab         import SkyTab
+from plot_tab        import PlotTab
+
+
+class MainWindow(QMainWindow):
+    def __init__(self, model: ReceiverManager):
+        super().__init__()
+        self._model = model
+        self.setWindowTitle("GNSS Monitor")
+        self.resize(1400, 900)
+
+        tabs = QTabWidget()
+        tabs.addTab(ConnectionTab(model), "Connection")
+        tabs.addTab(SkyTab(model),        "Sky")
+        tabs.addTab(PlotTab(model),       "Plot")
+        self.setCentralWidget(tabs)
+
+    def closeEvent(self, event):
+        for rid in list(self._model.get_receiver_ids()):
+            self._model.disconnect_receiver(rid)
+        event.accept()
+
+
+def main():
+    app = QApplication(sys.argv)
+    app.setStyle('Fusion')
+
+    model = ReceiverManager()
+    win   = MainWindow(model)
+    win.show()
+
+    sys.exit(app.exec_())
+
+
+if __name__ == '__main__':
+    main()