Investigate and add tests for potential memory leaks

[bomanaps]

We noticed some memory leaks in the codebase. While some fixes have been applied, we suspect not all issues have been addressed. To properly handle this, we need a structured investigation and tests that can reliably expose the leaks.

• fix: make start node test friendly and fix several memory leak #198
• Add CI simulation test for genesis generation to finalization #194

Next steps:

• Use memory profiling tools (Valgrind etc) to locate hotspots.
• Add a reproducible test case that highlights the leak(s).
• Investigate severity and prioritize fixes.

[GrapeBaBa]

I suspect there are a lot of memory leak issues hidden by the arena allocator used in tests. It should be changed to testing.allocator or gpa if multithread test. @g11tech @gballet