Add source code.

include/Models.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <optional>
+#include <string>
+
+struct TaskRow {
+    std::string id;
+    std::optional<std::string> account;
+    std::string status;  // serialized, see StatusUtil::serialize
+    std::string notes;   // free text, any length (stored as SQLite TEXT)
+};