fix: PHP 7.4 compat — remove union return types from session handler

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

middleware/DbSessionHandler.php

@@ -5,10 +5,10 @@ class DbSessionHandler implements SessionHandlerInterface
 {
     private const TTL = 86400 * 30; // 30 days
 
-    public function open(string $path, string $name): bool { return true; }
+    public function open($path, $name): bool { return true; }
     public function close(): bool { return true; }
 
-    public function read(string $id): string|false
+    public function read($id): string
     {
         $stmt = db()->prepare("SELECT data FROM sessions WHERE id = ? AND updated_at > DATE_SUB(NOW(), INTERVAL " . self::TTL . " SECOND)");
         $stmt->execute([$id]);
@@ -16,23 +16,23 @@ class DbSessionHandler implements SessionHandlerInterface
         return $row ? $row['data'] : '';
     }
 
-    public function write(string $id, string $data): bool
+    public function write($id, $data): bool
     {
         db()->prepare("INSERT INTO sessions (id, data) VALUES (?, ?) ON DUPLICATE KEY UPDATE data = VALUES(data), updated_at = NOW()")
             ->execute([$id, $data]);
         return true;
     }
 
-    public function destroy(string $id): bool
+    public function destroy($id): bool
     {
         db()->prepare("DELETE FROM sessions WHERE id = ?")->execute([$id]);
         return true;
     }
 
-    public function gc(int $max_lifetime): int|false
+    public function gc($max_lifetime): int
     {
         $stmt = db()->prepare("DELETE FROM sessions WHERE updated_at < DATE_SUB(NOW(), INTERVAL ? SECOND)");
         $stmt->execute([self::TTL]);
-        return $stmt->rowCount();
+        return (int)$stmt->rowCount();
     }
 }