Best Value rows: capsule on its own line, comparison caption beneath

The verdict capsule shared a line with "vs closest eligible station"; the
caption's layoutPriority squeezed the capsule until it truncated
("Approx. £2.75 better off after tra…"), and in this sort mode the verdict
is the point of the row.

- The capsule now owns the line and the caption sits under it.
- The capsule text also shrinks rather than truncating at large Dynamic
  Type sizes, since nothing competes with it for width.
- The detail sheet keeps its side-by-side layout: it has the room, and the
  verdict there is the sheet's headline.

FuelBoard/FuelSavingsViews.swift

@@ -107,16 +107,19 @@ struct FuelSavingsSummaryView: View {
                 // break even, blue baseline. lineLimit + minimumScaleFactor keep
                 // it to one line, so rows stay even.
                 VStack(alignment: .leading, spacing: 2) {
-                    HStack(alignment: .firstTextBaseline, spacing: 6) {
+                    // The capsule gets the WHOLE line and the comparison caption
+                    // sits beneath it. Side by side, the caption's layoutPriority
+                    // squeezed the verdict until it truncated ("Approx. £2.75
+                    // better off after tra…"), and in this sort mode the verdict
+                    // is the point of the row.
                     capsule(for: result, compact: true)
                         .accessibilityLabel(accessibilityHeadline(for: result))
                     Text(comparisonLabel(for: result))
                         .font(.caption2)
                         .foregroundStyle(.secondary)
                         .lineLimit(1)
-                            .layoutPriority(1)
+                        .minimumScaleFactor(0.85)
                         .accessibilityLabel("Comparison: \(comparisonLabel(for: result))")
-                    }
                     if let warning = priceWarning ?? priceConfidence.warningText {
                         Text(warning)
                             .font(.caption2)
@@ -281,6 +284,10 @@ struct FuelSavingsSummaryView: View {
                 .accessibilityHidden(true)
             Text(result.capsuleHeadline())
                 .lineLimit(1)
+                // Belt and braces: now that the capsule owns its line it has no
+                // rival for width, and shrinking beats truncating at large
+                // Dynamic Type sizes.
+                .minimumScaleFactor(0.8)
         }
         .font(compact ? .caption.weight(.semibold) : .headline)
         .foregroundStyle(capsuleColor(for: result.status))