Enhance gacha banner functionality and improve stats management

[Js41637]

Summary

This branch overhauls the gacha import and statistics pipeline across Honkai: Star Rail, Genshin Impact, and Zenless Zone Zero.

• Introduces a shared import pipeline with deterministic deduplication, pool/item validation, provenance handling, conflict-safe persistence, and transactional stat recalculation.
• Makes multi-game UIGF imports atomic and recalculates stats even when an identical import changes no pull rows.
• Adds pool-aware banner classification with consistent win/loss fallback behavior across all three games.
• Completes ZZZ support for all six signal pools, including banners, personal/global statistics, imports, and UIGF exports.
• Batches global percentile updates and prevents non-finite luck or win-rate values.
• Hardens import jobs with opaque UUIDs, one active job per UID, redacted upstream URLs, and stable client-facing errors.
• Corrects per-game private-history authorization.
• Adds Mizuki to Genshin’s standard character pool.
• Fixes official European Genshin wish timestamps that were previously stored seven hours early.

Database changes

• Sanitizes existing NaN statistics and adds finite/range constraints.
• Adds pool metadata to HSR and Genshin banners.
• Adds ZZZ banner and missing pool-stat tables.
• Migrates existing official European Genshin wishes by +7 hours.

Existing Chronicled Wish and HSR collaboration banner rows should be reviewed after deployment for any pool-specific metadata backfills.