test(shell): 兼容源码契约测试换行符 / Make source contract tests line-ending agnostic

中文：
- 读取 Shell 集成契约引用的源码后移除回车符
- 避免 Windows CI 的 CRLF 检出导致多行断言误报

English:
- Remove carriage returns after reading sources used by shell integration contract checks
- Prevent CRLF checkouts in Windows CI from causing false failures in multiline assertions

验证 / Validation:
- scripts/test.bat（76/76 通过 / 76/76 passed）

Author: FreeFallingSnow

tests/shell_integration_contract_tests.cpp

@@ -1,3 +1,4 @@
+#include <algorithm>
 #include <filesystem>
 #include <fstream>
 #include <iostream>
@@ -24,7 +25,9 @@ std::string ReadFile(const std::filesystem::path& path)
         return {};
     std::ostringstream contents;
     contents << file.rdbuf();
-    return contents.str();
+    std::string source = contents.str();
+    source.erase(std::remove(source.begin(), source.end(), '\r'), source.end());
+    return source;
 }
 
 std::string_view FunctionBody(std::string_view source,