The quick-create field toggles used to live inside the quick create
popover; per feedback on MUL-4873 they belong in the Settings page.
Adds a My Account 'Issue' tab with one group per create mode backed by
a new per-workspace issue-create-settings store, extends field
visibility to the manual dialog (status/priority/assignee/labels/
project/due date/start date with value-reveal and overflow re-entry),
and routes both dialogs' 'Customize fields' items to the tab.
Co-authored-by: Lambda <lambda@multica.ai>
Co-authored-by: multica-agent <github@multica.ai>
