fix: prevent blocks lazy loading when no chat selected

src/lib/ChatScreens/DefaultChatScreen.svelte

@@ -51,6 +51,7 @@
     }
 
     $effect(() => {
+        if($selectedCharID < 0) return
         if(blocks.length-10 < DBState.db.characters[$selectedCharID].chats[DBState.db.characters[$selectedCharID].chatPage].message.length){
             blocks = new Uint8Array(blocks.length + 500)
             for(let i=0;i<500;i++){