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/Context/BotContext.php

@@ -87,7 +87,7 @@ class BotContext implements ContextInterface
      * @noinspection PhpDocMissingThrowsInspection
      * @noinspection PhpUnhandledExceptionInspection
      */
-    public function prompt(array|MessageSegment|string|\Stringable $prompt = '', int $timeout = 600, array|MessageSegment|string|\Stringable $timeout_prompt = '', int $option = ZM_PROMPT_NONE): null|array|OneBotEvent|string
+    public function prompt(array|MessageSegment|string|\Stringable $prompt = '', int $timeout = 600, array|MessageSegment|string|\Stringable $timeout_prompt = '', int $option = ZM_PROMPT_NONE): array|OneBotEvent|string|null
     {
         if (!container()->has('bot.event')) {
             throw new OneBot12Exception('bot()->prompt() can only be used in message event');
@@ -268,7 +268,7 @@ class BotContext implements ContextInterface
      * @return null|array|OneBotEvent|string 根据不同匹配类型返回不同的东西
      * @throws OneBot12Exception
      */
-    private function applyPromptReturn(mixed $result, int $option): null|array|OneBotEvent|string
+    private function applyPromptReturn(mixed $result, int $option): array|OneBotEvent|string|null
     {
         // 必须是 OneBotEvent 且是消息类型
         if (!$result instanceof OneBotEvent || $result->type !== 'message') {