Initialize ErrorHandler early and ensure immediate log file creation

- Added early initialization of `ErrorHandler` in `main.cc` for robust error handling.
- Modified `ErrorHandler` to create the log file immediately, ensuring its presence in the state directory.
- Simplified conditional checks for log file operations and updated timestamp handling to use `system_clock`.

main.cc

@@ -117,6 +117,9 @@ main(int argc, char *argv[])
 {
 	std::setlocale(LC_ALL, "");
 
+	// Ensure the error handler (and its log file) is initialised early.
+	kte::ErrorHandler::Instance();
+
 	Editor editor;
 
 	// CLI parsing using getopt_long