refs https://github.com/TryGhost/Team/issues/1390
- added `membersTimeFilters` feature flag and labs toggle
- added `<GhDatePicker>` component that lifts functionality from the `<GhDateTimePicker>` component
- `<GhDateTimePicker>` has not yet been refactored to use the new component internally as there are some odd/complex interactions with error handling with it's existing use-cases and they are in critical publishing paths so the refactor doesn't belong as part of this change
- added "Created at" filter type to members filters
- uses new date picker component for input value
- has "before", "on or before", "after", "on or after" operators
- "on" and "not on" operators were skipped as they require two NQL statements to represent, breaking the current 1:1 statement:filter approach used in the NQL-based query param parsing
refs. https://github.com/TryGhost/Ghost/issues/11445
- fixed input field background colors in Post Settings menu in darkmode
- applied color variables to day picker calendar component
- fixed colors of day picker calendar in darkmode
closes https://github.com/TryGhost/Ghost/issues/8249
- replaces the old split-button publish/schedule/update button with a less confusing menu system
- adds a `{{gh-date-time-picker}}` component that contains a datepicker with separate time input
- replaces the date text input in the post settings menu with `{{gh-date-time-picker}}`
- disabled when post is scheduled, only way to update a scheduled time is via the publish menu
- validates date is in the past when draft/published so there's no confusion with scheduling
- displays saving status in top-left of editor screen
- refactor editor (auto)saving processes to use ember-concurrency
Other minor changes:
- adds `post.publishedAtBlog{TZ,Date,Time}` properties to Post model to allow working with `publishedAt` datetime in the selected blog timezone rather than UTC
- adds a `beforeSave` hook to `validation-engine` that is called after successful validation and before the Ember Data save call is made
- adds validation of `publishedAtBlog{Date,Time}` to post validator
- prevent gh-task-button showing last task state on first render
- fixes bug where clicking into and out of the published date input in the PSM without making any changes saves a published date for draft posts
