optimizations (#2904)

* calc once, then re-use
* prevent invalid theme switch
* allow to turn off weekly-quick-entries by permissions
* remove 00:00 from date-times that likely do not need a time
* fix datepicker out of window

public/build/entrypoints.json

@@ -3,7 +3,7 @@
     "app": {
       "js": [
         "build/runtime.b8e7bb04.js",
-        "build/app.da44b7f8.js"
+        "build/app.3947eaef.js"
       ],
       "css": [
         "build/app.3bc2b4d9.css"