fix: make PCNTL extension optional for StdioServerTransport

Signal handling now gracefully degrades when PCNTL extension is unavailable or the event loop doesn't support signals. The transport continues to work normally since termination also happens when STDIN closes.

Author: CodeWithKyrian

composer.json

@@ -46,7 +46,7 @@
         "symfony/var-dumper": "^6.4.11|^7.1.5"
     },
     "suggest": {
-        "react/http": "Required for using the ReactPHP HTTP transport handler (^1.11 recommended)."
+        "ext-pcntl": "For signal handling support when using StdioServerTransport with StreamSelectLoop"
     },
     "autoload": {
         "psr-4": {

src/Transports/StdioServerTransport.php

@@ -148,12 +148,16 @@ public function listen(): void
             $this->close();
         });
 
-        $signalHandler = function (int $signal) {
-            $this->logger->info("Received signal {$signal}, shutting down.");
-            $this->close();
-        };
-        $this->loop->addSignal(SIGTERM, $signalHandler);
-        $this->loop->addSignal(SIGINT, $signalHandler);
+        try {
+            $signalHandler = function (int $signal) {
+                $this->logger->info("Received signal {$signal}, shutting down.");
+                $this->close();
+            };
+            $this->loop->addSignal(SIGTERM, $signalHandler);
+            $this->loop->addSignal(SIGINT, $signalHandler);
+        } catch (Throwable $e) {
+            $this->logger->debug('Signal handling not supported by current event loop.');
+        }
 
         $this->logger->info('Server is up and listening on STDIN 🚀');