feat: integrate generalized predicates into circuits

[vplasencia]

Description

This PR introduces generalized predicate functionality and refactors the claim value retrieval logic by moving it from the show circuit to the jwt circuit.

A document with full details of the generalized predicate design and implementation is available here: https://hackmd.io/@vplasencia/HyvshF0sbl

Related Issue(s)

Re #70

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Important

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