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/es-toolkit/dist/string/capitalize.d.mts

@@ -0,0 +1,16 @@
+//#region src/string/capitalize.d.ts
+/**
+ * Converts the first character of string to upper case and the remaining to lower case.
+ *
+ * @template T - Literal type of the string.
+ * @param str - The string to be converted to uppercase.
+ * @returns The capitalized string.
+ *
+ * @example
+ * const result = capitalize('fred') // returns 'Fred'
+ * const result2 = capitalize('FRED') // returns 'Fred'
+ */
+declare function capitalize<T extends string>(str: T): Capitalize<T>;
+type Capitalize<T extends string> = T extends `${infer F}${infer R}` ? `${Uppercase<F>}${Lowercase<R>}` : T;
+//#endregion
+export { capitalize };