refactor(dynamic): add recursive dependency resolution for C++ receivers, improve harness generation logic, and expand test coverage

tests/dynamic_fixtures/class_method/cpp_recursive_deps/benign.cpp

@@ -0,0 +1,29 @@
+// Benign control for recursive C++ class-method receiver construction.
+#include <string>
+
+class ShellRunner {
+public:
+    void exec(const std::string& _cmd) {}
+};
+
+class CommandRunner {
+    ShellRunner shell;
+
+public:
+    explicit CommandRunner(ShellRunner shell) : shell(shell) {}
+
+    void run(const std::string& input) {
+        shell.exec(input);
+    }
+};
+
+class UserService {
+    CommandRunner runner;
+
+public:
+    explicit UserService(CommandRunner runner) : runner(runner) {}
+
+    void run(const std::string& input) {
+        runner.run(input);
+    }
+};

tests/dynamic_fixtures/class_method/cpp_recursive_deps/vuln.cpp

@@ -0,0 +1,33 @@
+// C++ class-method fixture whose receiver has same-file constructor
+// dependencies but no default constructor.
+#include <cstdlib>
+#include <string>
+
+class ShellRunner {
+public:
+    void exec(const std::string& cmd) {
+        std::system(cmd.c_str());
+    }
+};
+
+class CommandRunner {
+    ShellRunner shell;
+
+public:
+    explicit CommandRunner(ShellRunner shell) : shell(shell) {}
+
+    void run(const std::string& input) {
+        shell.exec(std::string("true ") + input);
+    }
+};
+
+class UserService {
+    CommandRunner runner;
+
+public:
+    explicit UserService(CommandRunner runner) : runner(runner) {}
+
+    void run(const std::string& input) {
+        runner.run(input);
+    }
+};