Add validation schemas and improve texture handling

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.

schemas/sessionsserver/session/minecraft/profile/[uuid].js

@@ -0,0 +1,16 @@
+const z = require("zod")
+
+module.exports = {
+    GET: {
+        params: z.object({
+            uuid: z.string().length(32).regex(/^[0-9a-fA-F]+$/, { message: "Invalid UUID (no dashes expected)." })
+        }),
+        query: z.object({
+            unsigned: z.enum(["true", "false"]).optional()
+        }),
+        error: {
+            code: 204, 
+            message: "No content (UUID not found)"
+        }
+    }
+}