feat: enable noUncheckedIndexedAccess and fix resulting type errors

src/components/OnboardingTour.tsx

@@ -251,7 +251,7 @@ export default function OnboardingTour() {
   useEffect(() => {
   if (localStorage.getItem(TOUR_KEY)) return;
   const t = setTimeout(async () => {
-    const rect = await measureTarget(TOUR_STEPS[0].targetId);
+    const rect = await measureTarget(TOUR_STEPS[0]?.targetId ?? "");
     if (rect) {
       setTargetRect(rect);
       setVisible(true);
@@ -267,7 +267,7 @@ useEffect(() => {
     isFirstRender.current = false;
     return;
   }
-  measureTarget(TOUR_STEPS[stepIndex].targetId).then((rect) => {
+  measureTarget(TOUR_STEPS[stepIndex]?.targetId ?? "").then((rect) => {
     if (rect) {
       setTargetRect(rect);
       setTimeout(() => tooltipRef.current?.focus(), 50);
@@ -285,7 +285,7 @@ useEffect(() => {
   useEffect(() => {
   if (!visible) return;
   const onResize = () => {
-    measureTarget(TOUR_STEPS[stepIndex].targetId).then(setTargetRect);
+    measureTarget(TOUR_STEPS[stepIndex]?.targetId ?? "").then(setTargetRect);
   };
   window.addEventListener("resize", onResize);
   return () => window.removeEventListener("resize", onResize);
@@ -318,7 +318,7 @@ useEffect(() => {
       />
       <Spotlight rect={targetRect} />
       <Tooltip
-        step={TOUR_STEPS[stepIndex]}
+        step={TOUR_STEPS[stepIndex]!}
         stepIndex={stepIndex}
         totalSteps={TOUR_STEPS.length}
         rect={targetRect}

src/components/ThumbnailStrip.tsx

@@ -70,7 +70,7 @@ export default function ThumbnailStrip({
     for (let t = 0; t <= duration; t += intervalSeconds) {
       times.push(Math.min(t, duration - 0.1));
     }
-    if (times[times.length - 1] < duration - 0.5) {
+    if ((times[times.length - 1] ?? 0) < duration - 0.5) {
       times.push(duration - 0.1);
     }
 
@@ -79,7 +79,7 @@ export default function ThumbnailStrip({
     for (let i = 0; i < times.length; i++) {
       if (abortRef.current) break;
 
-      const time = times[i];
+      const time = times[i] ?? 0;
       await new Promise<void>((resolve) => {
         const onSeeked = () => {
           video.removeEventListener("seeked", onSeeked);
@@ -117,7 +117,7 @@ export default function ThumbnailStrip({
   const activeIndex = thumbnails.findIndex(
     (t, i) =>
       currentTime >= t.time &&
-      (i === thumbnails.length - 1 || currentTime < thumbnails[i + 1].time)
+      (i === thumbnails.length - 1 || currentTime < (thumbnails[i + 1]?.time ?? Infinity))
   );
 
   if (!videoSrc) return null;

src/components/TipCarousel.tsx

@@ -80,7 +80,8 @@ export default function TipCarousel() {
   };
 
   const activeTip = TIPS[activeIdx];
-  const IconComponent = activeTip.icon;
+  if (!activeTip) return null;
+  const IconComponent = activeTip.icon; 
 
   return (
     <div 

src/components/VideoEditor.tsx

@@ -401,7 +401,7 @@ export default function VideoEditor() {
                 {recommendedPreset && (
                   <div className="mb-4 rounded-2xl border border-film-200 bg-film-50 p-3 text-sm text-film-700">
                     <p>
-                      We detected a {recommendedPreset.label.replace(/\s/g, "")} video → Recommended: {recommendedPreset.platform.split("·")[0].trim()} ({recommendedPreset.label.replace(/\s/g, "")})
+                      We detected a {recommendedPreset.label.replace(/\s/g, "")} video → Recommended: {(recommendedPreset.platform.split("·")[0] ?? "").trim()} ({recommendedPreset.label.replace(/\s/g, "")})
                     </p>
                   </div>
                 )}

src/components/WaveformCanvas.tsx

@@ -54,7 +54,7 @@ export default function WaveformCanvas({ samples, loading, hasAudio }: Props) {
     ctx.globalAlpha = 0.7;
 
     for (let i = 0; i < samples.length; i++) {
-      const amplitude = samples[i];
+      const amplitude = samples[i] ?? 0;
       const barHeight = Math.max(amplitude * (height * 0.92), 1.5);
       const x = i * barWidth;
       const y = midY - barHeight / 2;

tsconfig.json

@@ -5,6 +5,7 @@
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
+    "noUncheckedIndexedAccess": true,
     "noEmit": true,
     "esModuleInterop": true,
     "module": "esnext",