refactor: finish ironpad migration

- finish ironpad migration but no test because it is not easy to test.

src/yycc/carton/ironpad.hpp

@@ -0,0 +1,83 @@
+#pragma once
+#include <string>
+#include <string_view>
+#include <optional>
+
+/**
+ * @brief Windows specific unhandled exception handler.
+ * @details
+ * This namespace is currently works on Windows.
+ * On other platforms, this namespace provided functions do nothing.
+ * For how to utilize this namespace, please see \ref exception_helper.
+ * 
+ * This feature is originate from my created Virtools plugin.
+ * Because its user frequently trigger some weird behaviors but I have no idea about the detail of them.
+ * So I create this feature. So that I can order user upload error log and coredump to help my debugging.
+ * The original implementation of this feature is copied from chirs241097's open source project whose name I forgotten.
+ * 
+ * After that, I split it from my plugin and let it become an independent library call IronPad,
+ * and use it in libcmo21 and etc.
+ * After few months, I created first version of YYCC and I move it into it and rename it as Exception Helper.
+ * 
+ * Now we entering the second major version of YYCC, I decide restore its original name and put it with other homebrew features.
+*/
+namespace yycc::carton::ironpad {
+
+    /**
+     * @brief The path info passed into user callback.
+     * @details
+     * For all pathes stored in this struct, if it is \c std::nullopt,
+     * it means that handler fail to create this, otherwise it must be created.
+     */
+    struct CallbackInfo {
+        std::optional<std::u8string> log_path;      ///< The path to crash log file.
+        std::optional<std::u8string> coredump_path; ///< The path to coredump file.
+    };
+
+    /**
+	 * @brief The callback function prototype which will be called when unhandled exception happened.
+	 * @details
+	 * During registering unhandled exception handler,
+	 * caller can optionally provide a function pointer matching this prorotype to register.
+	 * Then it will be called if unhandled exception hanppened.
+     * The timing of calling this callback is the end of writing all essential files and before exiting handler.
+     * In other words, all passed pathes are valid for visiting if they are not \c std::nullopt.
+	 * 
+	 * This callback is convenient for programmer using an explicit way to tell user an exception happened.
+	 * Because in default, handler will only write error log to \c stderr and file.
+	 * It will be totally invisible in GUI application.
+	*/
+    using ExceptionCallback = void (*)(const CallbackInfo& info);
+
+    /**
+	 * @brief Register unhandled exception handler
+	 * @details
+	 * This function will set an internal function as unhandled exception handler.
+	 * 
+	 * When unhandled exception raised, 
+	 * That internal function will output error stacktrace in standard output,
+	 * and generate log file and dump file in \c \%LOCALAPPDATA\%/IronPad folder if it is possible.
+	 * (for convenient debugging of developer when reporting bugs.)
+	 * 
+	 * This function usually is called at the start of program.
+	 * @param[in] callback User defined callback called when unhandled exception happened. nullptr if no callback.
+     * @return True when success, otherwise false.
+	*/
+    bool startup(ExceptionCallback callback = nullptr);
+
+    /**
+	 * @brief Unregister unhandled exception handler
+	 * @details 
+	 * The reverse operation of startup().
+	 * 
+	 * This function and startup() should always be used as a pair.
+	 * You must call this function to release reources if you have called startup().
+	 * 
+	 * This function usually is called at the end of program.
+     * 
+     * It is safe that call this function multiple times, or call this function when startup() return false.
+     * It means that there is no compulsory check for the return value of startup() if you don't care it.
+	*/
+    void shutdown();
+
+} // namespace yycc::carton::ironpad