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/upperCase.d.ts

@@ -0,0 +1,18 @@
+//#region src/string/upperCase.d.ts
+/**
+ * Converts a string to upper case.
+ *
+ * Upper case is the naming convention in which each word is written in uppercase and separated by an space ( ) character.
+ *
+ * @param str - The string that is to be changed to upper case.
+ * @returns The converted string to upper case.
+ *
+ * @example
+ * const convertedStr1 = upperCase('camelCase') // returns 'CAMEL CASE'
+ * const convertedStr2 = upperCase('some whitespace') // returns 'SOME WHITESPACE'
+ * const convertedStr3 = upperCase('hyphen-text') // returns 'HYPHEN TEXT'
+ * const convertedStr4 = upperCase('HTTPRequest') // returns 'HTTP REQUEST'
+ */
+declare function upperCase(str: string): string;
+//#endregion
+export { upperCase };