fix(web): viewport reactivity, off-screen thumbhashes being rendered (#15435)

* viewport optimizations

* fade in

* async bitmap

* fast path for smaller date groups

---------

Co-authored-by: Alex <alex.tran1502@gmail.com>

web/package.json

@@ -86,8 +86,7 @@
     "svelte-gestures": "^5.1.3",
     "svelte-i18n": "^4.0.1",
     "svelte-local-storage-store": "^0.6.4",
-    "svelte-maplibre": "^0.9.13",
-    "thumbhash": "^0.1.1"
+    "svelte-maplibre": "^0.9.13"
   },
   "volta": {
     "node": "22.14.0"