Fix the day picker's workout-day dots missing on most days

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

Workouts/Views/Today/TodayView.swift

@@ -288,9 +288,20 @@ struct TodayView: View {
     }
 
     /// Day-precision (year/month/day) components of every day with at least one
-    /// logged workout — the day picker decorates these with a dot.
+    /// logged workout — the day picker decorates these with a dot. Built as *bare*
+    /// y/m/d components, not `dateComponents([.year, .month, .day], from:)` output:
+    /// the latter also sets `isLeapMonth = false`, which `==` ignores but hashing
+    /// doesn't — so a bare-components `Set.contains` probe (the day picker's) would
+    /// miss every member.
     private var workoutDays: Set<DateComponents> {
-        Set(workouts.map { Calendar.current.dateComponents([.year, .month, .day], from: $0.start) })
+        Set(workouts.map { workout in
+            let c = Calendar.current.dateComponents([.year, .month, .day], from: workout.start)
+            var day = DateComponents()
+            day.year = c.year
+            day.month = c.month
+            day.day = c.day
+            return day
+        })
     }
 
     /// Row icon color: the routine's own color, or the goal's color as a generic