Viewer-local weekly grids must resolve adjacent source weeks

When a weekly schedule stores shifts in one authoritative timezone but displays them in each viewer’s timezone, a local Monday–Sunday grid cannot be built from the identically dated source week alone. Resolve stored intervals as absolute instants, load adjacent source weeks that can cross the viewer-local boundary, and group each interval by its viewer-local start date. Comparing equal-named calendar columns across timezones is invalid because a shift may move to the next day or beyond the displayed week.

Limit: this applies when product semantics group by shift start; coverage-overlap views need a different projection.

Applies when: A calendar renders authoritative schedules for viewers in different timezones. Keywords: schedule timezone local week adjacent boundary shift start