feat: Add persistent localStorage for Kabelstrecken (polylines) visibility

- Add kabelstreckenVisible state with localStorage persistence
- Implement dual localStorage variables (kabelstreckenVisible + polylineVisible) for compatibility
- Add event system for cross-component polyline visibility updates
- Update MapComponent to listen for polylineVisibilityChanged events
- Ensure polylines display correctly on browser reload
- Migrate from Redux-only state to localStorage-first approach
- Add comprehensive debug logging for troubleshooting

Fixes issue where Kabelstrecken checkbox state was lost on page reload
and polylines were not displayed until manual toggle.

redux/slices/database/polylines/polylineLayerVisibleSlice.js

@@ -2,7 +2,8 @@
 import { createSlice } from "@reduxjs/toolkit";
 
 const initialState = {
-  visible: false, // oder Standardwert
+  visible: false, // Standardwert - wird in der Komponente aus localStorage überschrieben
+  isInitialized: false, // Flag um zu verfolgen, ob der Wert aus localStorage geladen wurde
 };
 
 const polylineLayerVisibleSlice = createSlice({
@@ -11,11 +12,21 @@ const polylineLayerVisibleSlice = createSlice({
   reducers: {
     setPolylineVisible: (state, action) => {
       state.visible = action.payload;
-      localStorage.setItem("polylineVisible", action.payload);
+      state.isInitialized = true;
+      localStorage.setItem("polylineVisible", action.payload.toString());
+      console.log("💾 Redux: setPolylineVisible called with:", action.payload);
+    },
+    initializePolylineFromLocalStorage: (state, action) => {
+      // Diese Action wird nur beim Initialisieren aus localStorage verwendet
+      state.visible = action.payload;
+      state.isInitialized = true;
+      console.log("🔧 Redux: initializePolylineFromLocalStorage called with:", action.payload);
     },
   },
 });
 
-export const { setPolylineVisible } = polylineLayerVisibleSlice.actions;
-export const selectPolylineVisible = (state) => state.polylineLayerVisible.visible;
+export const { setPolylineVisible, initializePolylineFromLocalStorage } =
+  polylineLayerVisibleSlice.actions;
+export const selectPolylineVisible = state => state.polylineLayerVisible.visible;
+export const selectPolylineInitialized = state => state.polylineLayerVisible.isInitialized;
 export default polylineLayerVisibleSlice.reducer;