fix: add SIGHUP/SIGTERM handling, modernize PHP support and CI

Signal handling fixes:
- SignalListener: add SIGHUP/SIGTERM handling for both Swoole
  and Workerman drivers in master and worker processes
- Prevent 100% CPU when IDE terminal is closed by ensuring
  graceful shutdown on terminal hangup

PHP version support:
- Widen PHP constraint to 8.3, 8.4, 8.5
- Bump doctrine/dbal from ^2.13.1 to ^4.4
- Bump php-cs-fixer to ^3.64, phpstan to ^1.12
- Bump swoole/ide-helper to ^5.0
- Drop phpunit ^8.5 (EOL), keep ^9.0

CI updates:
- actions/checkout@v3 → @v4 (Node.js 20 deprecated)
- Bump static analysis/code style PHP from 8.1 to 8.3

src/ZM/Store/KV/Redis/KVRedis.php

@@ -35,7 +35,7 @@ class KVRedis implements KVInterface
         return $ret;
     }
 
-    public function set(string $key, mixed $value, null|\DateInterval|int $ttl = null): bool
+    public function set(string $key, mixed $value, \DateInterval|int|null $ttl = null): bool
     {
         /** @var ZMRedis $redis */
         $redis = RedisPool::pool($this->pool_name)->get();
@@ -78,7 +78,7 @@ class KVRedis implements KVInterface
         RedisPool::pool($this->pool_name)->put($redis);
     }
 
-    public function setMultiple(iterable $values, null|\DateInterval|int $ttl = null): bool
+    public function setMultiple(iterable $values, \DateInterval|int|null $ttl = null): bool
     {
         /** @var ZMRedis $redis */
         $redis = RedisPool::pool($this->pool_name)->get();