Add settings page for managing forecasting API key and URL via UI

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/node_modules/recharts/es6/util/createEventProxy.js

@@ -0,0 +1,16 @@
+export function createEventProxy(reactEvent) {
+  reactEvent.persist();
+  var currentTarget = reactEvent.currentTarget;
+  return new Proxy(reactEvent, {
+    get: (target, prop) => {
+      if (prop === 'currentTarget') {
+        return currentTarget;
+      }
+      var value = Reflect.get(target, prop);
+      if (typeof value === 'function') {
+        return value.bind(target);
+      }
+      return value;
+    }
+  });
+}