Add carousel tabs and selection-based nav to save editor

Wrap save editor tab buttons in a Carousel to prevent overflow on
desktop. Carousel nav buttons now cycle through the selected item
(save slot or tab) instead of scrolling, with auto-scroll-into-view.
On mobile, tabs reflow with flex-wrap as before.

src/app.css

@@ -505,6 +505,8 @@ body {
     font-weight: bold;
     cursor: pointer;
     transition: all 0.2s ease;
+    white-space: nowrap;
+    flex-shrink: 0;
 }
 
 .config-tab-btn:hover {

src/lib/Carousel.svelte

@@ -4,6 +4,13 @@
 
     export let gap = 10;
 
+    // Optional selection-based navigation. When provided, nav buttons
+    // change the selected item instead of scrolling.
+    export let onPrev = null;
+    export let onNext = null;
+    export let hasPrev = undefined;
+    export let hasNext = undefined;
+
     let trackRef;
     let canScrollLeft = false;
     let canScrollRight = false;
@@ -14,6 +21,9 @@
     // Exposed so parent can check if a drag occurred (to prevent click handling)
     export let hasDragged = false;
 
+    $: leftDisabled = hasPrev !== undefined ? !hasPrev : !canScrollLeft;
+    $: rightDisabled = hasNext !== undefined ? !hasNext : !canScrollRight;
+
     function updateArrows() {
         if (!trackRef) return;
         const { scrollLeft, scrollWidth, clientWidth } = trackRef;
@@ -21,13 +31,41 @@
         canScrollRight = scrollLeft + clientWidth < scrollWidth - 1;
     }
 
-    function scrollLeft() {
+    function handleLeft() {
+        if (onPrev) {
+            onPrev();
+        } else {
             trackRef?.scrollBy({ left: -200, behavior: 'smooth' });
         }
+    }
 
-    function scrollRight() {
+    function handleRight() {
+        if (onNext) {
+            onNext();
+        } else {
             trackRef?.scrollBy({ left: 200, behavior: 'smooth' });
         }
+    }
+
+    function scrollChildIntoView(child) {
+        const trackRect = trackRef.getBoundingClientRect();
+        const childRect = child.getBoundingClientRect();
+        const isFullyVisible = childRect.left >= trackRect.left && childRect.right <= trackRect.right;
+
+        if (!isFullyVisible) {
+            const scrollTarget = childRect.left < trackRect.left
+                ? trackRef.scrollLeft - (trackRect.left - childRect.left)
+                : trackRef.scrollLeft + (childRect.right - trackRect.right);
+            trackRef.scrollTo({ left: scrollTarget, behavior: 'smooth' });
+        }
+    }
+
+    /** Scroll the nth child (0-indexed) into view */
+    export function scrollToIndex(index) {
+        if (!trackRef) return;
+        const child = trackRef.children[index];
+        if (child) scrollChildIntoView(child);
+    }
 
     function handleMouseDown(e) {
         if (e.button !== 0) return;
@@ -55,24 +93,9 @@
     }
 
     function handleClick(e) {
-        // Find the direct child element that was clicked
         const clickedCard = e.target.closest('.carousel-track > *');
         if (!clickedCard || hasDragged) return;
-
+        scrollChildIntoView(clickedCard);
-        const trackRect = trackRef.getBoundingClientRect();
-        const cardRect = clickedCard.getBoundingClientRect();
-
-        // Check if card is fully visible
-        const isFullyVisible = cardRect.left >= trackRect.left && cardRect.right <= trackRect.right;
-
-        if (!isFullyVisible) {
-            // Scroll to bring card into view
-            const scrollLeft = cardRect.left < trackRect.left
-                ? trackRef.scrollLeft - (trackRect.left - cardRect.left)
-                : trackRef.scrollLeft + (cardRect.right - trackRect.right);
-
-            trackRef.scrollTo({ left: scrollLeft, behavior: 'smooth' });
-        }
     }
 
     onMount(() => {
@@ -86,7 +109,7 @@
 </script>
 
 <div class="carousel">
-    <NavButton direction="left" onclick={scrollLeft} disabled={!canScrollLeft} />
+    <NavButton direction="left" onclick={handleLeft} disabled={leftDisabled} />
     <!-- svelte-ignore a11y_click_events_have_key_events a11y_no_static_element_interactions a11y_no_noninteractive_element_interactions -->
     <div
         class="carousel-track"
@@ -103,7 +126,7 @@
     >
         <slot />
     </div>
-    <NavButton direction="right" onclick={scrollRight} disabled={!canScrollRight} />
+    <NavButton direction="right" onclick={handleRight} disabled={rightDisabled} />
 </div>
 
 <style>

src/lib/SaveEditorPage.svelte

@@ -53,6 +53,46 @@
 
     // Carousel state (bound from Carousel component)
     let carouselHasDragged = false;
+    let slotCarousel;
+    let tabCarousel;
+
+    // Slot carousel navigation
+    $: selectedSlotIndex = existingSlots.findIndex(s => s.slotNumber === selectedSlot);
+    $: hasSlotPrev = selectedSlotIndex > 0;
+    $: hasSlotNext = selectedSlotIndex >= 0 && selectedSlotIndex < existingSlots.length - 1;
+
+    function selectPrevSlot() {
+        if (!hasSlotPrev) return;
+        const newIdx = selectedSlotIndex - 1;
+        handleSlotSelect(existingSlots[newIdx].slotNumber);
+        slotCarousel?.scrollToIndex(newIdx);
+    }
+
+    function selectNextSlot() {
+        if (!hasSlotNext) return;
+        const newIdx = selectedSlotIndex + 1;
+        handleSlotSelect(existingSlots[newIdx].slotNumber);
+        slotCarousel?.scrollToIndex(newIdx);
+    }
+
+    // Tab carousel navigation
+    $: activeTabIndex = saveTabs.findIndex(t => t.id === activeTab);
+    $: hasTabPrev = activeTabIndex > 0;
+    $: hasTabNext = activeTabIndex < saveTabs.length - 1;
+
+    function selectPrevTab() {
+        if (!hasTabPrev) return;
+        const newIdx = activeTabIndex - 1;
+        switchTab(saveTabs[newIdx]);
+        tabCarousel?.scrollToIndex(newIdx);
+    }
+
+    function selectNextTab() {
+        if (!hasTabNext) return;
+        const newIdx = activeTabIndex + 1;
+        switchTab(saveTabs[newIdx]);
+        tabCarousel?.scrollToIndex(newIdx);
+    }
 
     onMount(async () => {
         await loadSlots();
@@ -278,7 +318,7 @@
         </div>
         <div class="config-main">
             {#if loading || error || existingSlots.length > 0}
-                <Carousel bind:hasDragged={carouselHasDragged}>
+                <Carousel bind:this={slotCarousel} bind:hasDragged={carouselHasDragged} onPrev={selectPrevSlot} onNext={selectNextSlot} hasPrev={hasSlotPrev} hasNext={hasSlotNext}>
                     {#if loading}
                         <span class="save-status-text">Loading save files...</span>
                     {:else if error}
@@ -326,7 +366,8 @@
 
             {#if currentSlot && currentSlot.exists}
                 <div class="config-tabs">
-                    <div class="config-tab-buttons">
+                    <div class="config-tab-buttons tab-carousel-wrapper">
+                        <Carousel bind:this={tabCarousel} gap={5} onPrev={selectPrevTab} onNext={selectNextTab} hasPrev={hasTabPrev} hasNext={hasTabNext}>
                             {#each saveTabs as tab}
                                 <button
                                     class="config-tab-btn"
@@ -336,6 +377,7 @@
                                     {tab.label}
                                 </button>
                             {/each}
+                        </Carousel>
                     </div>
 
                     <!-- Player Tab -->
@@ -607,6 +649,42 @@
         image-rendering: pixelated;
     }
 
+    .tab-carousel-wrapper {
+        display: block;
+    }
+
+    .tab-carousel-wrapper :global(.carousel) {
+        gap: 4px;
+    }
+
+    .tab-carousel-wrapper :global(.carousel-track) {
+        cursor: default;
+    }
+
+    .tab-carousel-wrapper :global(.carousel-track.dragging) {
+        cursor: default;
+    }
+
+    @media (max-width: 768px) {
+        .tab-carousel-wrapper {
+            display: flex;
+            flex-wrap: wrap;
+            gap: 0;
+        }
+
+        .tab-carousel-wrapper :global(.carousel) {
+            display: contents;
+        }
+
+        .tab-carousel-wrapper :global(.nav-btn) {
+            display: none;
+        }
+
+        .tab-carousel-wrapper :global(.carousel-track) {
+            display: contents;
+        }
+    }
+
     @media (max-width: 400px) {
         .name-slot {
             width: 32px;