Expose PBC data via C

[Cryoris]

What should we add?

We should allow C users to iterate over the circuits and retrieve the PBC instruction data for performant access (and Python-free access from Rust). This requires #15450, exposing PauliProductMeasurements and PauliEvolutionGate to C, and deciding how we expose generic circuit parameters to C (probably akin to QkOperationType in the DAG circuit).