The decorated-days set was built from dateComponents([.year, .month,
.day], from:) output, which also sets isLeapMonth = false; the day
picker probes it with bare y/m/d components (isLeapMonth nil). The two
compare == but hash differently, so Set.contains missed essentially
every member and dots appeared only on chance hash collisions. Build
the set from bare y/m/d components matching the probe's shape.
Claude-Session: https://claude.ai/code/session_012qw2itfzKyEJ1HpsFt8Ex4
rzen
20d7f00843