QoL: Visualize Dateranges within the Datepicker

• Nextcloud-Version: 33.0.5.1 (Docker)
• Forms-Version: 5.4.0

Problem:
When answering a form containing a date picker with a start- and/or end-date range, it mostly has to be communicated in the question/description. This can sometimes be some hassle for the user, especially if the range cannot be displayed within the same month.

Suggestion:
I would suggest adding a client-side visualization adjustment of the datepicker, where the allowed and not allowed dates, if given, are colored accordingly.

Additional Thoughts:
Implementation should be without major changes, as the user already receives the start/end detail of the question by default when loading the form. Furthermore, with the new change that these ranges are saved as a Datestring instead of a Unix timestamp, this might further simplify this implementation (assuming older Forms, which are still using Unix timestamps, are not supposed to get this QoL improvement).

Two example mockup images of how it could look (the valid time range is, in this example, 18.08-22.08):

Start by locating the client-side datepicker and the existing handling for start and end dates, then inspect how the newer date-string ranges are represented. The work is done when allowed and disallowed dates are visibly distinguished across month boundaries without changing date selection behavior.