fix: puzzle sidebar integrates into layout instead of overlapping waveform

- Puzzle panel now shifts canvas and waveform viewer right (340px) instead of
  overlapping them, using body class toggle and CSS transitions
- Canvas resize accounts for sidebar width
- Progress (completed/unlocked levels, custom components) persists in localStorage
- Level cards refresh on each panel open to reflect current progress

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

js/levels.js

@@ -127,13 +127,39 @@ export const LEVELS = [
     }
 ];
 
-// Progress tracking
-export const progress = {
-    unlockedLevels: ['buffer'],
-    completedLevels: [],
-    currentLevel: null,
-    customComponents: {}  // { name -> component definition }
-};
+// Progress tracking — load from localStorage if available
+function loadProgress() {
+    try {
+        const saved = localStorage.getItem('logiclab_progress');
+        if (saved) {
+            const parsed = JSON.parse(saved);
+            return {
+                unlockedLevels: parsed.unlockedLevels || ['buffer'],
+                completedLevels: parsed.completedLevels || [],
+                currentLevel: null,
+                customComponents: parsed.customComponents || {}
+            };
+        }
+    } catch (e) { /* ignore parse errors */ }
+    return {
+        unlockedLevels: ['buffer'],
+        completedLevels: [],
+        currentLevel: null,
+        customComponents: {}
+    };
+}
+
+function saveProgress() {
+    try {
+        localStorage.setItem('logiclab_progress', JSON.stringify({
+            unlockedLevels: progress.unlockedLevels,
+            completedLevels: progress.completedLevels,
+            customComponents: progress.customComponents
+        }));
+    } catch (e) { /* ignore storage errors */ }
+}
+
+export const progress = loadProgress();
 
 /**
  * Get all available levels for display
@@ -259,6 +285,8 @@ export function completeLevel(levelId) {
             progress.unlockedLevels.push(nextId);
         }
     }
+
+    saveProgress();
 }
 
 /**
@@ -270,6 +298,7 @@ export function registerComponent(name, gateTypes, connections) {
         gateTypes,
         connections
     };
+    saveProgress();
 }
 
 /**
@@ -294,4 +323,5 @@ export function resetProgress() {
     progress.completedLevels = [];
     progress.currentLevel = null;
     progress.customComponents = {};
+    saveProgress();
 }