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-lock.json

@@ -30,8 +30,7 @@
         "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"
       },
       "devDependencies": {
         "@eslint/eslintrc": "^3.1.0",
@@ -8209,11 +8208,6 @@
       "integrity": "sha512-AUwVmViIEUgBwxJJ7stnF0NkPpZxx1aZ6WiAbQ/Qq61h6I9UR4grXtZDmO8mnlaNORhHnIBlXJ1uBxILEKuVyw==",
       "license": "MIT"
     },
-    "node_modules/thumbhash": {
-      "version": "0.1.1",
-      "resolved": "https://registry.npmjs.org/thumbhash/-/thumbhash-0.1.1.tgz",
-      "integrity": "sha512-kH5pKeIIBPQXAOni2AiY/Cu/NKdkFREdpH+TLdM0g6WA7RriCv0kPLgP731ady67MhTAqrVG/4mnEeibVuCJcg=="
-    },
     "node_modules/timers-ext": {
       "version": "0.1.7",
       "resolved": "https://registry.npmjs.org/timers-ext/-/timers-ext-0.1.7.tgz",