- add Access frontend that publishes thread-safe ban manager snapshots for dedicated server use
- add BanManager storage for banned-players.json and banned-ips.json with load/save/update flows
- add persistent player and IP ban checks during dedicated server connection handling
- add UTF-8 BOM-safe JSON parsing and shared file helpers backed by nlohmann/json
- add Unicode-safe ban file read/write and safer atomic replacement behavior on Windows
- add active-ban snapshot APIs and expiry-aware filtering for expires metadata
- add RAII-based dedicated access shutdown handling during server startup and teardown
