Added

• Configurable api.max_api_payload_bytes limit (default 5 MB) guarding outgoing battle submissions; oversized payloads are automatically trimmed before submission via the new BattlePayloadSizeGuard.
• Battle submissions to the PvPIndex API are now gzip-compressed (Content-Encoding: gzip), reducing bandwidth for large replay payloads.
• Oversized submissions rejected by the API with HTTP 413 are automatically retried with replay frames stripped, instead of failing outright.
• New message key queue.arena_teleport_failed shown when a match cannot start because the arena world was not ready.

Changed

• Split the monolithic BattleService into focused collaborators (BattleStartHandler, BattleEndHandler, BattleSubmissionFlow, BattleSubmissionRetryHandler, BattlePayloadBuilder, BattleStartSetupStore) for clearer separation of concerns and easier testing.
• Extracted API request/compression helpers (ApiRequestBuilder, CompressionService) shared by the Paper API client.

Fixed

• Arena teleport failures no longer strand players in survival with their kit. BattleQueueService now checks the result of the arena teleport; on failure the match is aborted, both players' pre-battle state is restored, and queued players are automatically re-queued instead of being left in the arena template world wearing battle gear.
• Arena world save race on cleanup: arena worlds now have autosave disabled immediately after creation, and their folders are deleted a few ticks after unload (with retries) instead of synchronously, preventing NoSuchFileException on raids.dat / level.dat under Multiverse and similar world-management plugins.