fix: guard ALL saves behind ready — never save DEFAULT_STATE to server

Root cause: on refresh, store starts with DEFAULT_STATE (resources: 0).
Blur/interval/unload handlers saved this zero state before server load.
Fix: every save path checks useGameStore.getState().ready before writing.

Frontend/src/hooks/useSaveSync.ts

@@ -1,8 +1,9 @@
 // useSaveSync.ts — Auto-save game state to backend every 30s
-// Serveur = autorité. Cookie-based auth — credentials sent automatically.
+// Serveur = autorité. NEVER save before server state is loaded (ready guard).
 
 import { useEffect, useRef, useCallback, useState } from "react";
 import { useAuth } from "../context/AuthContext";
+import { useGameStore } from "../store/useGameStore";
 import type { GameState } from "../core/economy";
 
 const SAVE_INTERVAL_MS = 30_000; // 30 seconds
@@ -35,6 +36,7 @@ async function apiRequest(path: string, options: RequestInit = {}) {
 
 export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncOptions) {
   const { user } = useAuth();
+  const ready = useGameStore((s) => s.ready);
   const lastSaveRef = useRef<string | null>(null);
   const loadedRef = useRef(false);
   const [serverLoaded, setServerLoaded] = useState(false);
@@ -42,7 +44,6 @@ export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncO
   // Load save from server on mount (once, only if logged in)
   useEffect(() => {
     if (loadedRef.current || !user) {
-      // Not logged in → signal immediately
       if (!user) setServerLoaded(true);
       return;
     }
@@ -63,9 +64,9 @@ export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncO
     });
   }, [onLoad, user]);
 
-  // Save function
+  // Save function — GUARDED by ready (never save DEFAULT_STATE)
   const saveToServer = useCallback(async () => {
-    if (!user) return;
+    if (!user || !useGameStore.getState().ready) return;
 
     const gameState = getGameState();
     const result = await apiRequest("/save", {
@@ -78,25 +79,24 @@ export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncO
     }
   }, [getGameState, playTimeSeconds, user]);
 
-  // Auto-save interval
+  // Auto-save interval — only when ready
   useEffect(() => {
-    if (!user) return undefined;
+    if (!user || !ready) return undefined;
 
     const interval = setInterval(() => {
       saveToServer();
     }, SAVE_INTERVAL_MS);
 
     return () => clearInterval(interval);
-  }, [saveToServer, user]);
+  }, [saveToServer, user, ready]);
 
-  // Reload from server on tab focus (multi-tab/multi-browser sync)
+  // Multi-tab sync: save on blur, reload on focus — only when ready
   useEffect(() => {
     if (!user) return undefined;
 
     const handleFocus = () => {
       apiRequest("/save").then((data) => {
         if (data?.gameState && data.lastSave) {
-          // Only load if server save is newer than our last known save
           if (!lastSaveRef.current || new Date(data.lastSave) > new Date(lastSaveRef.current)) {
             onLoad(data.gameState);
             lastSaveRef.current = data.lastSave;
@@ -107,8 +107,8 @@ export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncO
     };
 
     const handleBlur = () => {
+      if (!useGameStore.getState().ready) return;
       saveToServer();
-      console.info("[SaveSync] Saved on blur — other tabs will get latest");
     };
 
     window.addEventListener("focus", handleFocus);
@@ -117,12 +117,12 @@ export function useSaveSync({ getGameState, onLoad, playTimeSeconds }: SaveSyncO
       window.removeEventListener("focus", handleFocus);
       window.removeEventListener("blur", handleBlur);
     };
-  }, [user, onLoad]);
+  }, [user, onLoad, saveToServer]);
 
-  // Save on page unload
+  // Save on page unload — GUARDED by ready
   useEffect(() => {
     const handleUnload = () => {
-      if (!user) return;
+      if (!user || !useGameStore.getState().ready) return;
 
       const gameState = getGameState();
       const payload = JSON.stringify({ gameState, playTimeSeconds });