Fix error handling for invalid clock times and task cancellations

- Add validation in LocalClockTime.init(dto:) to throw WeatherDTOMappingError.invalidClockTime instead of crashing on invalid hour/minute values
- Add CancellationError handling in loadWeather to prevent false error banners when location changes cancel in-flight requests

Author: cursoragent

example_projects/Weather/Weather/ContentView.swift

@@ -150,6 +150,8 @@ struct ContentView: View {
 
         do {
             report = try await weatherService.weather(for: locationID)
+        } catch is CancellationError {
+            return
         } catch {
             weatherErrorMessage = "Weather unavailable"
         }

example_projects/Weather/Weather/Services/WeatherClientDTOs.swift

@@ -142,6 +142,7 @@ enum WeatherDTOMappingError: Error, Equatable {
     case missingWeekday
     case invalidWeekday(Int)
     case invalidWindDirection(Double)
+    case invalidClockTime(hour: Int, minute: Int)
 }
 
 extension WeatherReport {
@@ -241,6 +242,9 @@ extension DailyForecast {
 
 private extension LocalClockTime {
     init(dto: LocalClockTimeDTO) throws {
+        guard (0...23).contains(dto.hour), (0...59).contains(dto.minute) else {
+            throw WeatherDTOMappingError.invalidClockTime(hour: dto.hour, minute: dto.minute)
+        }
         self.init(hour: dto.hour, minute: dto.minute)
     }
 }