Live Activity: move preset label to top-leading so it doesn't overlap y-axis labels

The chart's y-axis labels (175/150/125/100) render on the right side of
the plot, but the preset-name label (e.g. '🚴 Biking') was also at
top-trailing, so they crowded the same top-right corner. Switched the
ZStack alignment to .leading and updated the label padding from
trailing→leading so the preset sits in the empty top-left area.

Author: ps2

Loop Widget Extension/Live Activity/ChartView.swift

@@ -98,7 +98,7 @@ struct ChartView: View {
     }
 
     var body: some View {
-        ZStack(alignment: Alignment(horizontal: .trailing, vertical: .top)){
+        ZStack(alignment: Alignment(horizontal: .leading, vertical: .top)){
             Chart {
                 if let preset = self.preset, (preset.minValue > 0 || preset.maxValue > 0), predicatedData.count > 0, preset.endDate > Date.now.addingTimeInterval(.hours(-6)) {
                     let (presetMin, presetMax) = adjustedRange(min: preset.minValue, max: preset.maxValue)
@@ -179,7 +179,7 @@ struct ChartView: View {
                     }
                 }
                 .font(.footnote)
-                .padding(.trailing, 5)
+                .padding(.leading, 5)
                 .padding(.top, 2)
             }
         }