/**
 * Static key-value store for runtime configuration values.
 *
 * Used throughout the package for feature flags and settings that need to be
 * readable anywhere without passing parameters down the call stack.
 *
 * **Built-in keys:**
 * - `'enableCache'` — controls widget and query caching (default `true`).
 *   Set via `init()` parameters or toggled at runtime. Checked on every
 *   cache read/write in `QueryCacheManager` and `WidgetCacheManager`.
 *
 * @example
 * // Disable cache at runtime
 * Environments.setValue('enableCache', false)
 *
 * @example
 * // Read with a default value (returned when key has never been set)
 * const cacheOn = Environments.getValue('enableCache', true)
 */
export declare class Environments {
    static environments: Record<string, any>;
    /**
     * Retrieves a stored value by key.
     *
     * @param key - The key to look up.
     * @param defaultValue - Value returned when the key has never been set. Defaults to `null`.
     * @returns The stored value, or `defaultValue` if the key is absent.
     *
     * @example
     * Environments.getValue('enableCache', true)   // true if never set
     * Environments.getValue('myFlag', false)        // false if never set
     */
    static getValue(key: string, defaultValue?: any): any;
    /**
     * Stores a value under the given key. Overwrites any existing value.
     * Takes effect immediately — the next call to `getValue` with the same key
     * returns the new value.
     *
     * @param key - The key to store under.
     * @param value - The value to store.
     * @returns The `Environments` class itself for chaining.
     *
     * @example
     * Environments.setValue('enableCache', false)
     * Environments.setValue('myFlag', true).setValue('otherFlag', 42)
     */
    static setValue(key: string, value: any): typeof Environments;
}