Implemented the sync between feature and live activity timers for the ActivityReporting service in the Sample app target.

Apps/Attendi/Sources/Services/ActivityReporting.swift

@@ -46,7 +46,7 @@ final class ActivityReporting: Reporting {
             content: .init(
                 state: .init(
                     state: .recording,
-                    anchor: anchor,
+                    anchor: anchor.addingTimeInterval(Constant.Time.flooring),
                     elapsed: .zero
                 ),
                 staleDate: Date.now.addingTimeInterval(Constant.Time.stale)
@@ -65,7 +65,7 @@ final class ActivityReporting: Reporting {
         await update(
             state: .paused,
             anchor: nil,
-            elapsed: elapsed
+            elapsed: elapsed.rounded(.down)
         )
         #endif
     }
@@ -79,7 +79,7 @@ final class ActivityReporting: Reporting {
         #if os(iOS)
         await update(
             state: .recording,
-            anchor: anchor,
+            anchor: anchor.addingTimeInterval(Constant.Time.flooring),
             elapsed: .zero
         )
         #endif
@@ -95,7 +95,7 @@ final class ActivityReporting: Reporting {
         await update(
             state: .processing,
             anchor: nil,
-            elapsed: elapsed
+            elapsed: elapsed.rounded(.down)
         )
         #endif
     }
@@ -163,6 +163,12 @@ private extension ActivityReporting {
 private enum Constant {
     /// The time constants.
     enum Time {
+        /// The half second added to a running timer's anchor. The system counts the Live Activity's timer up from the anchor and
+        /// formats it with round-to-nearest, whereas the feature's own timer floors the elapsed seconds; moving the anchor half a
+        /// second into the future turns that rounding back into flooring, so both timers show the same whole second instead of the
+        /// Live Activity ticking one second ahead for the back half of each second.
+        static let flooring: TimeInterval = 0.5
+
         /// The span past which the system marks the recording Live Activity stale once the app stops updating it — because it was
         /// killed, for example — so an abandoned activity stops looking live instead of lingering for the activity's full lifetime.
         /// Generous enough to outlast a recording of any realistic length.