🧪 [Testing] Add unit test for serve.py build_state

[Ch3fUlrich]

🎯 What: This PR addresses a testing gap by adding unit tests for the serve.py build_state function.
📊 Coverage: The new tests in tests/run-tests.sh specifically test serve.build_state() by mocking subprocess.run to cover the happy path (which outputs correctly formatted valid JSON data describing system state and catalogs), and the error case handling scenarios where subprocess.run exits with a non-zero exit code.
✨ Result: The build_state logic in serve.py is now properly covered by unit tests, ensuring the robustness of this core function and that changes are protected from regression errors.

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PR created automatically by Jules for task 2210936461160254275 started by @Ch3fUlrich

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