Default to tasks.db in home directory

include/HomeDirectory.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <filesystem>
+
+/**
+ * @brief Retrieves the current user's home directory across different operating systems.
+ * 
+ * On Windows, it checks the USERPROFILE environment variable.
+ * On Unix/Linux/macOS, it checks the HOME environment variable, with a fallback
+ * to checking the password database entry (`getpwuid`) if HOME is unset.
+ * 
+ * @return std::filesystem::path Path to the user's home directory, or an empty path if unable to resolve.
+ */
+std::filesystem::path getHomeDirectory();