fix: LFO→cutoff modulation, visual knob feedback, persistent hints

- Fix LFO→Filter cutoff: add scaling Gain nodes so LFO (-1..1) maps to
  meaningful Hz modulation (±cutoff value). Same fix for LFO→Osc freq.
  Mod scale updates dynamically when user changes the base param value.
- Visual modulation indicator: knobs receiving LFO/modulation show a
  pulsing dashed ring animation (spin + pulse) around the knob arc
- Persist hint usage per level: using a hint permanently caps that level
  at 2 stars — survives reload/restart. No more cheating by restarting!
- Hint state stored in separate localStorage key (synthquest-hints)
- Admin reset also clears hint history

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

src/game/LevelComplete.jsx

@@ -14,7 +14,7 @@ export default function LevelComplete({ stars, checks, levelTitle, onNext, onRet
   const messages = [
     '',
     'Has dado el primer paso...',
-    hintPenalty ? 'Reinicia sin pista para conseguir 3 estrellas.' : 'Buen trabajo — casi perfecto.',
+    hintPenalty ? 'Pista usada — tercera estrella bloqueada permanentemente.' : 'Buen trabajo — casi perfecto.',
     'Ejecucion impecable.',
   ];
 
@@ -58,7 +58,7 @@ export default function LevelComplete({ stars, checks, levelTitle, onNext, onRet
         <div className="gm-complete-actions">
           <button className="gm-btn secondary" onClick={onMap}>Mapa</button>
           <button className="gm-btn secondary" onClick={onRetry}>
-            {hintPenalty ? '↺ Sin pista' : 'Reintentar'}
+            Reintentar
           </button>
           {stars >= 1 && !isLastLevel && (
             <button className="gm-btn primary" onClick={onNext}>Siguiente →</button>

src/game/PuzzleView.jsx

@@ -6,7 +6,7 @@ import ModuleNode from '../components/ModuleNode.jsx';
 import WireLayer from '../components/WireLayer.jsx';
 import { playTarget, stopTarget, isTargetPlaying } from './targetAudio.js';
 import LevelComplete from './LevelComplete.jsx';
-import { completeLevel, saveLevelPatch, getLevelPatch } from './gameState.js';
+import { completeLevel, saveLevelPatch, getLevelPatch, markHintUsed, wasHintUsed } from './gameState.js';
 
 export default function PuzzleView({ level, levelIndex, worldLevels, onBack, onNextLevel }) {
   const [, forceUpdate] = useState(0);
@@ -76,8 +76,10 @@ export default function PuzzleView({ level, levelIndex, worldLevels, onBack, onN
       deserialize(data);
     }
     setResult(null);
-    setHintUsed(false);
-    setShowHint(false);
+    // Restore persisted hint state — no cheating by reloading!
+    const hintPersisted = wasHintUsed(level.id);
+    setHintUsed(hintPersisted);
+    setShowHint(hintPersisted); // If they used it before, show it again
     if (state.isRunning) stopAudio();
   }, [level]);
 
@@ -245,10 +247,11 @@ export default function PuzzleView({ level, levelIndex, worldLevels, onBack, onN
     }
   };
 
-  // Reveal hint — permanently caps this attempt at 2 stars
+  // Reveal hint — PERMANENTLY caps this level at 2 stars (persisted, survives reload)
   const handleRevealHint = () => {
     setHintUsed(true);
     setShowHint(true);
+    markHintUsed(level.id);
   };
 
   const handleCheck = () => {
@@ -357,7 +360,7 @@ export default function PuzzleView({ level, levelIndex, worldLevels, onBack, onN
             })}
             {hintUsed && (
               <div className="gm-hint-warning">
-                Pista usada — maximo 2 estrellas. Reinicia para intentar sin pista.
+                Pista usada — maximo 2 estrellas en este nivel (permanente).
               </div>
             )}
           </div>

src/game/gameState.js

@@ -61,8 +61,10 @@ export function isLevelUnlocked(levelId, worldLevels) {
 export function resetProgress() {
   _progress = { ...defaultProgress };
   _patches = {};
+  _hints = {};
   saveProgress();
   savePatches();
+  saveHints();
 }
 
 // ==================== Level patch persistence ====================
@@ -105,3 +107,43 @@ export function clearLevelPatch(levelId) {
   delete patches[levelId];
   savePatches();
 }
+
+// ==================== Hint tracking (persisted, no cheating!) ====================
+
+const HINTS_KEY = 'synthquest-hints';
+let _hints = null; // { levelId: true }
+
+function loadHints() {
+  if (_hints) return _hints;
+  try {
+    const raw = localStorage.getItem(HINTS_KEY);
+    _hints = raw ? JSON.parse(raw) : {};
+  } catch {
+    _hints = {};
+  }
+  return _hints;
+}
+
+function saveHints() {
+  if (!_hints) return;
+  try {
+    localStorage.setItem(HINTS_KEY, JSON.stringify(_hints));
+  } catch {}
+}
+
+export function markHintUsed(levelId) {
+  const hints = loadHints();
+  hints[levelId] = true;
+  saveHints();
+}
+
+export function wasHintUsed(levelId) {
+  const hints = loadHints();
+  return !!hints[levelId];
+}
+
+export function clearHintForLevel(levelId) {
+  const hints = loadHints();
+  delete hints[levelId];
+  saveHints();
+}