Better WebConsole

Added

• New Audit tab for recent authentication, command and player-action audit events.
• Search and refresh controls for audit history.
• Built-in favicon asset.

Improved

• Web sessions are now persisted as SHA-256 token hashes instead of raw session tokens.
• Existing session storage is migrated automatically on next startup.
• Dashboard stats now use cached snapshots, reducing extra Bukkit main-thread work from web clients.
• Chart.js is bundled with the plugin frontend instead of loaded from a CDN.