feat: redesign asset-viewer previous/next and hide when nav not possible (#24903)

web/src/routes/(user)/folders/[[photos=photos]]/[[assetId=id]]/+page.svelte

@@ -103,7 +103,6 @@
     {#if data.pathAssets && data.pathAssets.length > 0}
       <div bind:clientHeight={viewport.height} bind:clientWidth={viewport.width} class="mt-2">
         <GalleryViewer
-          initialAssetId={data.asset?.id}
           assets={data.pathAssets}
           {assetInteraction}
           {viewport}

web/src/routes/(user)/map/[[photos=photos]]/[[assetId=id]]/+page.svelte

@@ -24,7 +24,6 @@
   let { isViewing: showAssetViewer, asset: viewingAsset, setAssetId } = assetViewingStore;
 
   let viewingAssets: string[] = $state([]);
-  let viewingAssetCursor = 0;
 
   onDestroy(() => {
     assetViewingStore.showAssetViewer(false);
@@ -36,28 +35,9 @@
 
   async function onViewAssets(assetIds: string[]) {
     viewingAssets = assetIds;
-    viewingAssetCursor = 0;
     await setAssetId(assetIds[0]);
   }
 
-  async function navigateNext() {
-    if (viewingAssetCursor < viewingAssets.length - 1) {
-      await setAssetId(viewingAssets[++viewingAssetCursor]);
-      await navigate({ targetRoute: 'current', assetId: $viewingAsset.id });
-      return true;
-    }
-    return false;
-  }
-
-  async function navigatePrevious() {
-    if (viewingAssetCursor > 0) {
-      await setAssetId(viewingAssets[--viewingAssetCursor]);
-      await navigate({ targetRoute: 'current', assetId: $viewingAsset.id });
-      return true;
-    }
-    return false;
-  }
-
   async function navigateRandom() {
     if (viewingAssets.length <= 0) {
       return undefined;
@@ -138,13 +118,11 @@
     </div>
   </UserPageLayout>
   <Portal target="body">
-    {#if $showAssetViewer}
+    {#if $showAssetViewer && assetCursor.current}
       {#await import('$lib/components/asset-viewer/asset-viewer.svelte') then { default: AssetViewer }}
         <AssetViewer
           cursor={assetCursor}
           showNavigation={viewingAssets.length > 1}
-          onNext={navigateNext}
-          onPrevious={navigatePrevious}
           onRandom={navigateRandom}
           onClose={() => {
             assetViewingStore.showAssetViewer(false);

web/src/routes/(user)/utilities/large-files/[[photos=photos]]/[[assetId=id]]/+page.svelte

@@ -20,32 +20,12 @@
   let assets = $derived(data.assets);
   let asset = $derived(data.asset);
   const { isViewing: showAssetViewer, asset: viewingAsset, setAsset } = assetViewingStore;
-  const getAssetIndex = (id: string) => assets.findIndex((asset) => asset.id === id);
-
   $effect(() => {
     if (asset) {
       setAsset(asset);
     }
   });
 
-  const onNext = async () => {
-    const index = getAssetIndex($viewingAsset.id) + 1;
-    if (index >= assets.length) {
-      return false;
-    }
-    await onViewAsset(assets[index]);
-    return true;
-  };
-
-  const onPrevious = async () => {
-    const index = getAssetIndex($viewingAsset.id) - 1;
-    if (index < 0) {
-      return false;
-    }
-    await onViewAsset(assets[index]);
-    return true;
-  };
-
   const onRandom = async () => {
     if (assets.length <= 0) {
       return undefined;
@@ -94,8 +74,6 @@
       <AssetViewer
         cursor={assetCursor}
         showNavigation={assets.length > 1}
-        {onNext}
-        {onPrevious}
         {onRandom}
         {onAction}
         onClose={() => {