docs: add package comments to auth and audit packages

internal/audit/service.go

@@ -1,3 +1,4 @@
+// Package audit provides audit logging for user actions.
 package audit
 
 import (

internal/auth/handler.go

@@ -1,3 +1,4 @@
+// Package auth provides authentication and session management.
 package auth
 
 import (