Get rid of 0 -1 sentinel values

Rig occasionally uses 0 to mean infinite, should probably switch those to Option types or use NonZerou64 magic

Find where 0 and -1 sentinel values are used to represent infinite or missing values in the codebase. Replace them with Option types or NonZeroU64 as appropriate. Look for patterns in numeric handling, especially in configuration or limit settings. Run existing tests to ensure the refactor doesn't break functionality.

索引モデルが issue の本文から書いたものです。