with a Copy button.',
	 * ]
	 *
	 * @return array[]
	 */
	public function ui_notices(): array {
		return array();
	}

	/**
	 * WP-CLI command definitions. Each entry: [
	 *   'name'     => 'xspeed cache purge',
	 *   'callback' => callable,
	 *   'synopsis' => array, // wp-cli synopsis spec
	 * ]
	 *
	 * @return array[]
	 */
	public function cli_commands(): array {
		return array();
	}

	/**
	 * Nginx directives this module contributes to the unified server-block
	 * snippet rendered by Cache::full_nginx_server_block(). Returning a
	 * non-null string opts the module into the consolidated "paste this
	 * once into your nginx vhost" UX on the Cache panel.
	 *
	 * The returned string should be the bare directives only — no `server
	 * { }` wrapper, no comment header (the aggregator adds one). Empty
	 * string and null are both treated as "no contribution this render".
	 *
	 * Return null (default) when the module is disabled, its current
	 * settings make the directives a no-op, or the module doesn't have
	 * nginx-side directives at all.
	 */
	public function nginx_directives(): ?string {
		return null;
	}

	/**
	 * Conflict declarations for this module — which other plugins clash
	 * with which sub-feature. Each entry: [
	 *   'plugin'   => 'wp-rocket/wp-rocket.php',
	 *   'feature'  => 'page_cache',
	 *   'strategy' => 'refuse' | 'warn' | 'allow',
	 *   'reason'   => 'human-readable why',
	 * ]
	 *
	 * @return array[]
	 */
	public function conflicts(): array {
		return array();
	}

	/**
	 * Register WP hooks. Called by Module_Registry::boot_all() after
	 * dependencies are resolved. Modules should NOT register hooks in
	 * their constructors — only in boot() — so the registry can control
	 * load order.
	 */
	public function boot(): void {}

	/**
	 * One-time setup at plugin activation. Idempotent. Examples: create
	 * a custom table, write a silence guard, register a cron schedule.
	 */
	public function activate(): void {}

	/**
	 * Tear down at plugin deactivation. Reversible counterpart to
	 * activate(). MUST leave the site in a clean state — no orphaned
	 * cron jobs, no leftover drop-ins.
	 */
	public function deactivate(): void {}

	/**
	 * Convenience accessors. Modules read/write their own settings
	 * through these so the storage detail (one option per module under
	 * `xspeed_module_`) stays encapsulated.
	 */
	final public function get_setting( string $key, $default = null ) {
		$opts = Settings_Manager::get( static::SLUG );
		return array_key_exists( $key, $opts ) ? $opts[ $key ] : $default;
	}

	final public function get_settings(): array {
		return Settings_Manager::get( static::SLUG );
	}

	final public function update_settings( array $input ): array {
		return Settings_Manager::update( static::SLUG, $input );
	}

	final public function slug(): string {
		return static::SLUG;
	}

	final public function tier(): string {
		return static::TIER;
	}

	final public function version(): string {
		return static::VERSION;
	}
}