update own todo list

transaction-processor/.todo-list

 - externalize openapi contract into separate artifact
-- using rabbitmq is probably an overkill for our small project. Either @async or a pure java/spring mock implementation of messaging?
-- rethink messaging and the handler pattern
+- handler for cross-account transaction
+- exchange rate API for currency conversion
+- custom exception classes
+- handler for exceptions -> Controller Advice
+- implementation for status and rollback/revert of transaction
+
+
+- TESTS TESTS TESTS
+- review within teammates projects / branches (bude toho dost asi zejo)
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