Update horizon-auth.md

Author: tristanpoland

public/blogs/horizon-auth.md

@@ -1,6 +1,6 @@
 title: "Event-Driven Authentication and Connection Management"
 date: "2025-07-19"
-categories: ["Engineering", "Multiplayer", "Gaming", "Rust", "Architecture"]
+categories: ["Engineering", "Multiplayer", "Gaming", "Rust", "Architecture", "Security"]
 tags: ["GameDev", "Rust", "Authentication", "Plugin Architecture", "Event System", "Performance", "External Integration", "Testing", "Security"]
 
 # Building Robust Authentication: Core Events and Connection Management in Horizon