feat: timeline performance (#16446)

* Squash - feature complete

* remove need to init assetstore

* More optimizations. No need to init. Fix tests

* lint

* add missing selector for e2e

* e2e selectors again

* Update: fully reactive store, some transitions, bugfixes

* merge fallout

* Test fallout

* safari quirk

* security

* lint

* lint

* Bug fixes

* lint/format

* accidental commit

* lock

* null check, more throttle

* revert long duration

* Fix intersection bounds

* Fix bugs in intersection calculation

* lint, tweak scrubber ui a tiny bit

* bugfix - deselecting asset doesnt work

* fix not loading bucket, scroll off-by-1 error, jsdoc, naming

web/src/lib/stores/asset-interaction.svelte.ts

@@ -5,8 +5,14 @@ import { fromStore } from 'svelte/store';
 
 export class AssetInteraction {
   readonly selectedAssets = new SvelteSet<AssetResponseDto>();
+  hasSelectedAsset(assetId: string) {
+    return [...this.selectedAssets.values()].some((asset) => asset.id === assetId);
+  }
   readonly selectedGroup = new SvelteSet<string>();
   assetSelectionCandidates = $state(new SvelteSet<AssetResponseDto>());
+  hasSelectionCandidate(assetId: string) {
+    return [...this.assetSelectionCandidates.values()].some((asset) => asset.id === assetId);
+  }
   assetSelectionStart = $state<AssetResponseDto | null>(null);
   focussedAssetId = $state<string | null>(null);
 
@@ -32,7 +38,10 @@ export class AssetInteraction {
   }
 
   removeAssetFromMultiselectGroup(asset: AssetResponseDto) {
-    this.selectedAssets.delete(asset);
+    const selectedAsset = [...this.selectedAssets.values()].find((a) => a.id === asset.id);
+    if (selectedAsset) {
+      this.selectedAssets.delete(selectedAsset);
+    }
   }
 
   addGroupToMultiselectGroup(group: string) {