feat: implement Favorites feature with persistent storage and sidebar integration and update lake data.

public/data/VLL2.json

@@ -6797,7 +6797,7 @@
   {
     "timestamp": "2026-06-05T21:00:00.000Z",
     "level": 559.91,
-    "flow": 0,
+    "flow": 7.18,
     "inflow": 0,
     "volume": 0,
     "temperature": 17.97824695485787,
@@ -6806,7 +6806,7 @@
   {
     "timestamp": "2026-06-05T21:10:00.000Z",
     "level": 559.9,
-    "flow": 0,
+    "flow": 7.18,
     "inflow": 0,
     "volume": 0,
     "temperature": 17.97824695485787,
@@ -6816,6 +6816,24 @@
     "timestamp": "2026-06-05T21:20:00.000Z",
     "level": 559.89,
     "flow": 0,
+    "inflow": 0,
+    "volume": 0,
+    "temperature": 17.97824695485787,
+    "precipitation": 0
+  },
+  {
+    "timestamp": "2026-06-05T21:30:00.000Z",
+    "level": 559.88,
+    "flow": 0,
+    "inflow": 0,
+    "volume": 0,
+    "temperature": 17.97824695485787,
+    "precipitation": 0
+  },
+  {
+    "timestamp": "2026-06-05T21:40:00.000Z",
+    "level": 559.87,
+    "flow": 0,
     "inflow": 3.71,
     "volume": 0.68,
     "temperature": 8.7,