Adds DecoTemplatesScreen mirroring TemplatesScreen: list mode groups deco
templates by deco template group with create/delete dialogs; editor mode
(/app/deco-templates/{id}) has an add-content row (deco group -> deco ->
start time -> duration hours/minutes pickers), a time-sorted items table
displaying end-of-day items as "24:00", and client-side validation mirroring
ReplaceDecoTemplateItemsHandler's hardened rules (start must precede its
effective end time; no overlapping ranges, with EndTime 00:00:00 treated as
end-of-day for both checks) that disables Save on violation.
No copy action: neither the Blazor DecoTemplateEditor nor the CQRS layer has
a deco-template copy command (unlike Templates, which has both Copy* and a
/copy route), so this isn't a parity gap - just matches upstream scope.
Registered at /app/deco-templates in the primary nav, next to Decos.
timothy
2b54a2d591