feat: Add player state management to turtle store

client/src/store/turtleStore.js

@@ -10,6 +10,7 @@ console.log('📡 API URL:', API_URL);
 export const useTurtleStore = create((set, get) => ({
   // State
   turtles: {},
+  players: {},
   worldBlocks: [],
   selectedTurtleId: null,
   connected: false,
@@ -65,6 +66,17 @@ export const useTurtleStore = create((set, get) => ({
               selectedTurtleId: newSelectedId
             };
           });
+        } else if (data.type === 'player_update') {
+          set(state => ({
+            players: {
+              ...state.players,
+              [data.playerID]: {
+                playerID: data.playerID,
+                position: data.position,
+                timestamp: data.timestamp
+              }
+            }
+          }));
         }
       } catch (error) {
         console.error('Error processing message:', error);