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

@@ -123,7 +123,7 @@
 
   async function navigateRandom() {
     if (viewingAssets.length <= 0) {
-      return null;
+      return undefined;
     }
     const index = Math.floor(Math.random() * viewingAssets.length);
     const asset = await setAssetId(viewingAssets[index]);