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/promise/mutex.mjs

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+import { Semaphore } from "./semaphore.mjs";
+//#region src/promise/mutex.ts
+/**
+* A Mutex (mutual exclusion lock) for async functions.
+* It allows only one async task to access a critical section at a time.
+*
+* @example
+* const mutex = new Mutex();
+*
+* async function criticalSection() {
+*   await mutex.acquire();
+*   try {
+*     // This code section cannot be executed simultaneously
+*   } finally {
+*     mutex.release();
+*   }
+* }
+*
+* criticalSection();
+* criticalSection(); // This call will wait until the first call releases the mutex.
+*/
+var Mutex = class {
+	semaphore = new Semaphore(1);
+	/**
+	* Checks if the mutex is currently locked.
+	* @returns True if the mutex is locked, false otherwise.
+	*
+	* @example
+	* const mutex = new Mutex();
+	* console.log(mutex.isLocked); // false
+	* await mutex.acquire();
+	* console.log(mutex.isLocked); // true
+	* mutex.release();
+	* console.log(mutex.isLocked); // false
+	*/
+	get isLocked() {
+		return this.semaphore.available === 0;
+	}
+	/**
+	* Acquires the mutex, blocking if necessary until it is available.
+	* @returns A promise that resolves when the mutex is acquired.
+	*
+	* @example
+	* const mutex = new Mutex();
+	* await mutex.acquire();
+	* try {
+	*   // This code section cannot be executed simultaneously
+	* } finally {
+	*   mutex.release();
+	* }
+	*/
+	async acquire() {
+		return this.semaphore.acquire();
+	}
+	/**
+	* Releases the mutex, allowing another waiting task to proceed.
+	*
+	* @example
+	* const mutex = new Mutex();
+	* await mutex.acquire();
+	* try {
+	*   // This code section cannot be executed simultaneously
+	* } finally {
+	*   mutex.release(); // Allows another waiting task to proceed.
+	* }
+	*/
+	release() {
+		this.semaphore.release();
+	}
+};
+//#endregion
+export { Mutex };