Keep HR chart annotations stable while scrolling

Packages/StrandDesign/Sources/StrandDesign/OverviewHRChart.swift

@@ -29,13 +29,17 @@ public struct OverviewHRChart: View {
     }
 
     /// A workout window; the sport glyph is placed at the HR peak inside [start, end].
-    public struct WorkoutSpan: Identifiable, Sendable {
-        public let id = UUID()
+    public struct WorkoutSpan: Identifiable, Sendable, Hashable {
+        // Today reconstructs annotations on redraw; unchanged spans must retain chart identity.
+        public var id: Self { self }
         public var start: Date
         public var end: Date
         public var symbol: String          // SF Symbol (see `sportSymbol`)
-        public init(start: Date, end: Date, symbol: String) {
+        public var sport: String?
+        public var source: String?
+        public init(start: Date, end: Date, symbol: String, sport: String? = nil, source: String? = nil) {
             self.start = start; self.end = end; self.symbol = symbol
+            self.sport = sport; self.source = source
         }
     }
 
@@ -150,6 +154,10 @@ public struct OverviewHRChart: View {
     /// Smallest zoom window we allow (1 minute) — past this the line is just two points and pinch jitters.
     public static let minZoomSpan: TimeInterval = 60
 
+    static func isHorizontalPan(_ translation: CGSize) -> Bool {
+        abs(translation.width) > abs(translation.height)
+    }
+
     // MARK: Zoom / pan math (pure, testable in isolation)
 
     /// The visible domain after scaling `base` about `anchorFraction` (0…1 across the window) by
@@ -711,6 +719,9 @@ private struct ZoomPanModifier: ViewModifier {
         // the 6–8 pt overlap band is what let a held-then-dragged finger begin panning during a scrub.
         let drag = DragGesture(minimumDistance: 10)
             .onChanged { value in
+                #if os(iOS)
+                guard OverviewHRChart.isHorizontalPan(value.translation) else { return }
+                #endif
                 let base = anchor ?? current()
                 if anchor == nil { anchor = base }
                 apply(pan(base, value.translation.width, plotWidth, bounds))

Packages/StrandDesign/Tests/StrandDesignTests/OverviewHRChartAnnotationTests.swift

@@ -20,6 +20,32 @@ final class OverviewHRChartAnnotationTests: XCTestCase {
     /// A day window: 86 400 s starting at t=100 000 (arbitrary epoch, values only matter relatively).
     private let day: ClosedRange<Date> = Date(timeIntervalSince1970: 100_000)...Date(timeIntervalSince1970: 186_400)
 
+    func testRebuiltWorkoutAnnotationsKeepIdentity() {
+        let original = workout(110_000, 113_600)
+        XCTAssertEqual(original.id, workout(110_000, 113_600).id)
+        XCTAssertNotEqual(original.id, workout(110_000, 114_000).id)
+        let otherSport = OverviewHRChart.WorkoutSpan(start: original.start, end: original.end,
+                                                     symbol: "figure.walk")
+        XCTAssertNotEqual(original.id, otherSport.id)
+        let saved = OverviewHRChart.WorkoutSpan(start: original.start, end: original.end,
+                                                symbol: "figure.run", sport: "Running", source: "manual")
+        let imported = OverviewHRChart.WorkoutSpan(start: original.start, end: original.end,
+                                                   symbol: "figure.run", sport: "Running", source: "import")
+        XCTAssertNotEqual(saved.id, imported.id, "Coincident annotations from different sources remain distinct")
+    }
+
+    func testVerticalScrollingDoesNotPanTheChart() {
+        for dx in [-8.0, 0, 8] {
+            for dy in [-30.0, 30] {
+                XCTAssertFalse(OverviewHRChart.isHorizontalPan(CGSize(width: dx, height: dy)))
+            }
+        }
+        XCTAssertFalse(OverviewHRChart.isHorizontalPan(.zero))
+        XCTAssertFalse(OverviewHRChart.isHorizontalPan(CGSize(width: 20, height: 20)))
+        XCTAssertTrue(OverviewHRChart.isHorizontalPan(CGSize(width: -30, height: 8)))
+        XCTAssertTrue(OverviewHRChart.isHorizontalPan(CGSize(width: 30, height: -8)))
+    }
+
     // MARK: mainSleep — the main night, never a nap
 
     /// The LONGEST overlapping block wins, exactly like the classic Today: a 7h night beats a 40m nap.

Strand/Screens/FullDayChartView.swift

@@ -404,7 +404,7 @@ struct FullDayChartView: View {
             .map { w in
                 .init(start: Date(timeIntervalSince1970: TimeInterval(w.startTs)),
                       end: Date(timeIntervalSince1970: TimeInterval(w.endTs)),
-                      symbol: sportSymbol(w.sport))
+                      symbol: sportSymbol(w.sport), sport: w.sport, source: w.source)
             }
         guard !Task.isCancelled else { return }
         // The pure, headless-tested selection (StrandDesignTests) — window = the shown DAY, not the zoom.

Strand/Screens/TodayView.swift

@@ -3774,7 +3774,7 @@ struct TodayView: View {
             let start = Date(timeIntervalSince1970: TimeInterval(w.startTs))
             let end = Date(timeIntervalSince1970: TimeInterval(w.endTs))
             guard end >= win.lowerBound, start <= win.upperBound else { return nil }
-            return .init(start: start, end: end, symbol: sportSymbol(w.sport))
+            return .init(start: start, end: end, symbol: sportSymbol(w.sport), sport: w.sport, source: w.source)
         }
     }