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/trimEnd.d.mts

@@ -0,0 +1,20 @@
+//#region src/string/trimEnd.d.ts
+/**
+ * Removes trailing whitespace or specified characters from a string.
+ *
+ * If `chars` is a string, it should be a single character. To trim a string with multiple characters,
+ * provide an array instead.
+ *
+ * @param str - The string from which trailing characters will be trimmed.
+ * @param chars - The character(s) to remove from the end of the string.
+ * @returns The resulting string after the specified trailing character has been removed.
+ *
+ * @example
+ * const trimmedStr1 = trimEnd('hello---', '-') // returns 'hello'
+ * const trimmedStr2 = trimEnd('123000', '0') // returns '123'
+ * const trimmedStr3 = trimEnd('abcabcabc', 'c') // returns 'abcabcab'
+ * const trimmedStr4 = trimEnd('trimmedxxx', 'x') // returns 'trimmed'
+ */
+declare function trimEnd(str: string, chars?: string | string[]): string;
+//#endregion
+export { trimEnd };