feat: implement turbine loading from DB and improved error reporting

app.js

@@ -1440,11 +1440,11 @@ document.addEventListener('DOMContentLoaded', async () => {
                     body: JSON.stringify({ projekt_id, turbines: turbineData })
                 });
 
+                const result = await response.json();
                 if (response.ok) {
-                    const result = await response.json();
                     statusEl.innerHTML = `<span style="color: #2ecc71;">${result.message}</span>`;
                 } else {
-                    throw new Error("Fehler beim Speichern in DB");
+                    throw new Error(result.error || "Fehler beim Speichern in DB");
                 }
             } catch (err) {
                 console.error(err);
@@ -1453,6 +1453,45 @@ document.addEventListener('DOMContentLoaded', async () => {
         });
     }
 
+    async function loadTurbinesFromDB() {
+        const project_id = "BWSamern-Ohne";
+        const statusEl = document.getElementById('statusInfo');
+        try {
+            const response = await fetch(`/api/wea/${project_id}`);
+            if (response.ok) {
+                const dbTurbines = await response.json();
+                if (dbTurbines.length > 0) {
+                    console.log(`Geladen: ${dbTurbines.length} WEAs aus der Datenbank.`);
+                    
+                    // Optional: Clear existing turbines if they were loaded from shapefile
+                    // but usually DB should take precedence
+                    state.turbines.forEach(t => {
+                        Object.values(t.layers).forEach(l => variantLayers[t.variant].removeLayer(l));
+                    });
+                    state.turbines = [];
+
+                    dbTurbines.forEach(t => {
+                        const latlng = L.latLng(t.lat, t.lng);
+                        createTurbine(latlng, null, {
+                            nr: t.nr,
+                            type: t.type,
+                            rd: t.rd,
+                            hh: t.hh
+                        });
+                    });
+                    statusEl.innerText = `${dbTurbines.length} WEAs aus Datenbank geladen.`;
+                }
+            }
+        } catch (err) {
+            console.error("Fehler beim Laden aus der DB:", err);
+        }
+    }
+
+    // Load from DB after layers are initialized
+    initDynamicLayers().then(() => {
+        loadTurbinesFromDB();
+    });
+
     btnLoad.addEventListener('click', () => projectInput.click());
 
     projectInput.addEventListener('change', (e) => {