P2E: add reward terms rules and support flow

[ilyar]

Source PRD: tasks/prd-full-play-to-earn.md
Parent epic: #86
PRD section: US-012

Description

Reward campaigns need official rules, terms acceptance, bot/support commands, and support lookup paths.

Acceptance Criteria

• Each reward campaign links to official rules.
• Rules state eligibility, reward pool, start/end time, reward formula, claim deadline, payout method, disqualification rules, support path, and sponsor/operator identity.
• UI requires acceptance of reward terms before claim.
• Bot supports /terms, /support, and /paysupport where relevant.
• Support can look up reward claims by account ID, campaign ID, payout ID, and provider reference.
• Terms copy is reviewed before public launch.

Constraints

• Keep current paid PvP settlement as entry fee, not player-funded prize pool.
• Do not make Season Points redeemable or refundable.
• Keep payout/compliance/provider secrets backend-only.
• Treat this as deferred future-phase work until mechanics/self-host production readiness is stable.

Notes

This issue should not write legal copy as final policy; it must create the product/technical hooks and review path.