Fix: supprime la transition slides-wrapper pendant le redimensionnement

Classe is-resizing ajoutée sur resize, retirée 150ms après le dernier
événement — évite le glissement animé lors du resize de fenêtre.

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

src/App.svelte

@@ -33,7 +33,17 @@
   const wrapperWidth = $derived(`${slides.all.length * 100}vw`)
   const wrapperTransform = $derived(`translateX(-${slides.activeIndex * 100}vw)`)
 
+  let isResizing = $state(false)
+  let resizeTimer = null
+
   onMount(() => {
+    const handleResize = () => {
+      isResizing = true
+      clearTimeout(resizeTimer)
+      resizeTimer = setTimeout(() => { isResizing = false }, 150)
+    }
+    window.addEventListener('resize', handleResize)
+
     const handleKeydown = (e) => {
       if (e.key === 'ArrowRight') {
         const next = slides.all[slides.activeIndex + 1]
@@ -44,7 +54,11 @@
       }
     }
     window.addEventListener('keydown', handleKeydown)
-    return () => window.removeEventListener('keydown', handleKeydown)
+    return () => {
+      window.removeEventListener('resize', handleResize)
+      window.removeEventListener('keydown', handleKeydown)
+      clearTimeout(resizeTimer)
+    }
   })
 </script>
 
@@ -54,6 +68,7 @@
 <main class="main">
   <div
     class="slides-wrapper"
+    class:is-resizing={isResizing}
     style="width: {wrapperWidth}; transform: {wrapperTransform}"
   >
     {#each slides.all as slide}
@@ -109,6 +124,10 @@
     transition: transform 1000ms cubic-bezier(0.77, 0, 0.175, 1);
   }
 
+  .slides-wrapper.is-resizing {
+    transition: none;
+  }
+
   .slide {
     width: 100vw;
     height: 100vh;