Moved sessionserver routes to correct directory and removed subdirectory logic from texture file lookup. Updated texture URLs to remove leading slashes and fixed endpoint concatenation. Added default textures for Alex and Steve.
Introduces zod-based validation schemas for Minecraft and Mojang API endpoints. Refactors texture route to support hash-based file serving and removes the old static texture route. Updates database schema for player properties and adds an event to clean expired certificates. Improves ValidationError formatting, adjusts skin/cape URL construction, and adds SSRF protection for skin uploads.
