Add finite-field and polynomial norm-recovery primitives

[spaceships]

Used for grinding part of pufferfish

[spaceships]

21. Fq12 square testing and square roots

 Implement and test correct extension-field square operations independently of polynomial factorization.

22. Polynomial square roots modulo irreducibles

 Add quotient-ring square-root support using the existing polynomial context.

23. Polynomial rational reconstruction

 Implement reconstruction and its degree-bound/error handling.

[odraccir1]

This is needed in the grinding part of Pufferfish, to check if the H poly is a norm