* add datetime var operations
* add future annotations
* add LiteralDatetimeVar
* remove methods that don't apply
* fix serialization
* add unit and integrations test
* oops, forgot to commit that important change
* add test for color mode (initial and toggle)
* add css check
* add page reload in the tests
* update test to catch the appearance regression
* don't render the appearance prop of rx.theme
* test for stateless apps
* add playwright to dev dependencies
* fix docstring
* fix install of playwright in CI
* fix install again
* add allowed license
* add retry on running integrations step
* another attempt to fix licensing issue
* update timeout duration for retry
* fix timeout workflows
* remove dep changes
* remove outdated diff
* fix scope in new test and workflow for appharness
* run playwright tests last
