feat: implement Dynamic Type with Apple text styles

Replace all custom Theme.FontSize values and hardcoded font sizes with
Apple's built-in text styles (.largeTitle, .title2, .headline, .body,
.subheadline, .caption, .caption2) to support accessibility scaling.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

SportsTime/Features/Trip/Views/RegionMapSelector.swift

@@ -144,11 +144,11 @@ struct RegionMapSelector: View {
 
             VStack(alignment: .leading, spacing: 1) {
                 Text(region.shortName)
-                    .font(.system(size: 11, weight: isSelected ? .bold : .medium))
+                    .font(.caption2)
                     .foregroundStyle(isSelected ? regionColor(region) : Theme.textPrimary(colorScheme))
 
                 Text(states)
-                    .font(.system(size: 9))
+                    .font(.caption2)
                     .foregroundStyle(Theme.textMuted(colorScheme))
             }
         }
@@ -159,7 +159,7 @@ struct RegionMapSelector: View {
         HStack(spacing: Theme.Spacing.md) {
             if selectedRegions.isEmpty {
                 Text("Tap map to select regions")
-                    .font(.system(size: Theme.FontSize.micro))
+                    .font(.caption)
                     .foregroundStyle(Theme.textMuted(colorScheme))
             } else {
                 Spacer()
@@ -168,7 +168,7 @@ struct RegionMapSelector: View {
                     selectedRegions.removeAll()
                 } label: {
                     Text("Clear")
-                        .font(.system(size: Theme.FontSize.micro))
+                        .font(.caption)
                         .foregroundStyle(Theme.warmOrange)
                 }
             }