Implement Real Groth16 Battle Circuit Constraints

[Steake]

Part of Epic: #72 - RC2: Zero-Knowledge Proof Production

---

Goal: Replace mock battle circuit with full R1CS constraints and production-ready Groth16 proof flow.

Requirements:

• Enforce CA evolution constraints verifying 1024x1024 grid according to Conway's rules
• Inputs: glider commitments, winner, seed, spawn positions
• Outputs: Proof that winner outcome is verifiable and reproducible
• Optimize for proving time <30s
• Test, compare against mock circuit

Acceptance Criteria:

• Circuit constraints enforce correct CA battle
• Proof generated and matches expected outcome
• All tests and benchmarks pass

See RELEASE_REQUIREMENTS. md

[Steake]

[autopilot] @copilot please start work on this issue and open a PR that references #44 in the PR description.