What

This MR bootstrap the addition of signature V3 in Octez crypto library and adapt the code where it is needed.

Why

Because we will need a new version of Signature in the coming future

Introduce Signature V3 and make it the latest signature version everywhere in the code.

This MR does not introduce anything except signature V3, the typing checks should do the trick

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
Select suitable reviewers using the Reviewers field below.
Select as Assignee the next person who should take action on that MR

Edited Dec 17, 2025 by Albin Coquereau