Implement file consistency check (validation)

TODO: Varidate all mapped links are exist (otherwise reset them to 0) (fast)
TODO: Varidate all freed link (holes). (slower)
TODO: Varidate all links. (slowest)

https://github.com/linksplatform/Data.Triplets.Kernel/blob/3520130be8f94cdd8eabd946b0bb94c423896a11/Platform.Data.Triplets.Kernel/PersistentMemoryManager.c#L403

Start at Platform.Data.Triplets.Kernel/PersistentMemoryManager.c around line 403 and trace how mapped links and freed-link holes are represented. Clarify the three validation modes in the issue, then define checks for each mode and verify that invalid mapped links are reset to 0. The issue does not mention specific tests, so completion should be demonstrated with coverage for all three validation cases.

Written by the indexing model from the issue text.