refactor; level reorder

src/storage.js

@@ -0,0 +1,51 @@
+(() => {
+  const makeStorageKey = (sceneId) => `physilinks-highscore-${sceneId}`;
+  const makeChainKey = (sceneId) => `physilinks-longestchain-${sceneId}`;
+
+  const loadHighScore = (sceneId) => {
+    try {
+      const raw = localStorage.getItem(makeStorageKey(sceneId));
+      const parsed = parseInt(raw, 10);
+      return Number.isFinite(parsed) ? parsed : 0;
+    } catch (err) {
+      console.error("Failed to load high score", { sceneId, err });
+      return 0;
+    }
+  };
+
+  const loadLongestChain = (sceneId) => {
+    try {
+      const raw = localStorage.getItem(makeChainKey(sceneId));
+      const parsed = parseInt(raw, 10);
+      return Number.isFinite(parsed) ? parsed : 0;
+    } catch (err) {
+      console.error("Failed to load longest chain", { sceneId, err });
+      return 0;
+    }
+  };
+
+  const saveHighScore = (sceneId, highScore) => {
+    try {
+      localStorage.setItem(makeStorageKey(sceneId), String(highScore));
+    } catch (err) {
+      console.error("Failed to save high score", { sceneId, err });
+    }
+  };
+
+  const saveLongestChain = (sceneId, longestChain) => {
+    try {
+      localStorage.setItem(makeChainKey(sceneId), String(longestChain));
+    } catch (err) {
+      console.error("Failed to save longest chain", { sceneId, err });
+    }
+  };
+
+  window.PhysilinksStorage = {
+    makeStorageKey,
+    makeChainKey,
+    loadHighScore,
+    loadLongestChain,
+    saveHighScore,
+    saveLongestChain,
+  };
+})();