Vetted Params presets

[cedoor]

Summary

Offer at least one vetted security-level Params preset alongside Params::unsecure(), so developers can ship something real without doing their own parameter analysis.

Background

Params::unsecure() is explicitly not a production security target. Developers who want to ship need a preset they can trust, but constructing and validating a secure parameter set requires deep FHE knowledge that most users don't have.

Work

• Define at least one vetted preset (e.g. targeting 128-bit security) validated against standard lattice estimators
• Expose it as e.g. Params::secure_128()
• Document the security claim, the assumptions it rests on, and its performance implications relative to Params::unsecure()