Both surfaces now show the same buckets with the same labels and the same
cutoffs: Überfällig (conditional, alarming) · Heute · Diese Woche ·
Nächste Woche · Erledigt. Single-source bucket math via
computeDeadlineBucketBounds — Heute = today, Diese Woche = tomorrow
through the upcoming Sunday inclusive, Nächste Woche = next Monday
through next Sunday inclusive, all disjoint. Items past next Sunday
are visible only via "All open"/"Upcoming" filters; the Überfällig
card stays hidden when count == 0 and switches to a saturated red
pulse + bold white text when count > 0.
Filter dropdown on /deadlines gains today / next_week entries; old
"upcoming" filter still works as a back-compat alias for everything
pending past this Sunday so legacy bookmarks don't 4xx.
Tests: 8 deterministic table cases for the bucket pivots (every
weekday + a 21-day disjointness walk).
37a925d3b2