Add feed refresh link (#5)

- Feed updates and refresh use the same logic
- Fixed issue with logic around item add-or-update

src/start.php

@@ -1,6 +1,8 @@
 <?php
+use JetBrains\PhpStorm\NoReturn;
+
 spl_autoload_register(function ($class) {
-    $file = implode(DIRECTORY_SEPARATOR, [ __DIR__, 'lib', "$class.php" ]);
+    $file = implode(DIRECTORY_SEPARATOR, [__DIR__, 'lib', "$class.php"]);
     if (file_exists($file)) {
         require $file;
         return true;
@@ -86,7 +88,8 @@ function page_foot(): void {
  *
  * @param string $value A local URL to which the user should be redirected
  */
-function frc_redirect(string $value) {
+#[NoReturn]
+function frc_redirect(string $value): void {
     if (str_starts_with($value, 'http')) {
         http_response_code(400);
         die();