Refactor exception handler to v3, use standard shell exitcode

src/StaticPHP/Command/ReturnCode.php

@@ -0,0 +1,42 @@
+<?php
+
+/** @noinspection PhpMissingClassConstantTypeInspection */
+
+declare(strict_types=1);
+
+namespace StaticPHP\Command;
+
+/**
+ * Return codes for command execution.
+ *
+ * This enum defines standard return codes that can be used by commands to indicate
+ * the result of their execution. It includes codes for success, various types of errors,
+ * and an interrupt signal.
+ */
+trait ReturnCode
+{
+    public const int OK = 0;
+
+    public const SUCCESS = 0; // alias of OK
+
+    public const int INTERNAL_ERROR = 1; // unsorted or internal error
+
+    /** @deprecated Use specified error code instead */
+    public const FAILURE = 1;
+
+    public const int USER_ERROR = 2; // wrong usage or user error
+
+    public const int ENVIRONMENT_ERROR = 3; // environment not suitable for operation
+
+    public const int VALIDATION_ERROR = 4; // validation failed
+
+    public const int FILE_SYSTEM_ERROR = 5; // file system related error
+
+    public const int DOWNLOAD_ERROR = 6; // network related error
+
+    public const int BUILD_ERROR = 7; // build process error
+
+    public const int PATCH_ERROR = 8; // patching process error
+
+    public const int INTERRUPT_SIGNAL = 130; // process interrupted by user (e.g., Ctrl+C)
+}