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/workbox-range-requests/utils/calculateEffectiveBoundaries.d.ts

@@ -0,0 +1,16 @@
+import '../_version.js';
+/**
+ * @param {Blob} blob A source blob.
+ * @param {number} [start] The offset to use as the start of the
+ * slice.
+ * @param {number} [end] The offset to use as the end of the slice.
+ * @return {Object} An object with `start` and `end` properties, reflecting
+ * the effective boundaries to use given the size of the blob.
+ *
+ * @private
+ */
+declare function calculateEffectiveBoundaries(blob: Blob, start?: number, end?: number): {
+    start: number;
+    end: number;
+};
+export { calculateEffectiveBoundaries };