P2E: add end-to-end reward economy tests

[ilyar]

Source PRD: tasks/prd-full-play-to-earn.md
Parent epic: #86
PRD section: US-014

Description

P2E needs deterministic tests for earning, claiming, payout status, eligibility blocks, and abuse holds.

Acceptance Criteria

• Local scenario covers match settlement -> reward points -> campaign finalization -> claimable reward.
• Fake payout provider scenario covers claim -> payout pending -> webhook paid.
• Tests verify entry fees do not fund or change reward pool balances.
• Tests verify ineligible users can play but cannot claim external-value rewards.
• Tests verify abuse-held rewards are not paid automatically.
• CI passes.

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

Keep public/cloud reward smoke manual until the full P2E layer is intentionally enabled.