🔧 fix: add @ConsistentCopyVisibility to MainNavState

Resolves Kotlin warning about data class copy() visibility
by opting into consistent copy visibility behavior where
copy() method has same visibility as constructor (private).

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: CXwudi

conduit-frontend/frontend-decompose-logic/src/commonMain/kotlin/mikufan/cx/conduit/frontend/logic/component/main/MainNav.model.kt

@@ -1,5 +1,6 @@
 package mikufan.cx.conduit.frontend.logic.component.main
 
+@ConsistentCopyVisibility
 data class MainNavState private constructor(
   val menuItems: List<MainNavMenuItem>,
   /**