[AZ-1126] Migrate capturedAt to DateTimeOffset

Co-authored-by: Cursor <cursoragent@cursor.com>

SatelliteProvider.Tests/Json/UtcOffsetRequiredDateTimeOffsetConverterTests.cs

@@ -0,0 +1,45 @@
+using System.Text.Json;
+using FluentAssertions;
+using SatelliteProvider.Common.DTO;
+using SatelliteProvider.Common.Json;
+
+namespace SatelliteProvider.Tests.Json;
+
+public class UtcOffsetRequiredDateTimeOffsetConverterTests
+{
+    private static readonly JsonSerializerOptions Options = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        Converters = { new UtcOffsetRequiredDateTimeOffsetConverter() },
+    };
+
+    [Theory]
+    [InlineData("\"2026-06-26T12:00:00Z\"")]
+    [InlineData("\"2026-06-26T12:00:00+00:00\"")]
+    [InlineData("\"2026-06-26T12:00:00.1234567Z\"")]
+    public void Deserialize_ExplicitUtcOffset_Parses(string capturedAtJson)
+    {
+        // Arrange
+        var json = $$"""{"latitude":50.1,"longitude":36.1,"tileZoom":18,"tileSizeMeters":200,"capturedAt":{{capturedAtJson}}}""";
+
+        // Act
+        var metadata = JsonSerializer.Deserialize<UavTileMetadata>(json, Options);
+
+        // Assert
+        metadata.Should().NotBeNull();
+        metadata!.CapturedAt.Offset.Should().Be(TimeSpan.Zero);
+    }
+
+    [Fact]
+    public void Deserialize_OffsetLessIsoString_ThrowsJsonException()
+    {
+        // Arrange
+        const string json = """{"latitude":50.1,"longitude":36.1,"tileZoom":18,"tileSizeMeters":200,"capturedAt":"2026-06-26T12:00:00"}""";
+
+        // Act
+        var act = () => JsonSerializer.Deserialize<UavTileMetadata>(json, Options);
+
+        // Assert
+        act.Should().Throw<JsonException>().WithMessage("*explicit UTC offset*");
+    }
+}

SatelliteProvider.Tests/UavTileQualityGateTests.cs

@@ -114,7 +114,7 @@ public class UavTileQualityGateTests
         var now = new DateTime(2026, 5, 11, 12, 0, 0, DateTimeKind.Utc);
         var gate = BuildGate(timeProvider: new FixedTimeProvider(now));
         var bytes = UavTileImageFactory.CreateRandomJpeg();
-        var metadata = ValidMetadata() with { CapturedAt = now.AddHours(1) };
+        var metadata = ValidMetadata() with { CapturedAt = new DateTimeOffset(now.AddHours(1), TimeSpan.Zero) };
 
         // Act
         var result = gate.Validate(bytes, JpegContentType, metadata);
@@ -131,7 +131,7 @@ public class UavTileQualityGateTests
         var now = new DateTime(2026, 5, 11, 12, 0, 0, DateTimeKind.Utc);
         var gate = BuildGate(timeProvider: new FixedTimeProvider(now));
         var bytes = UavTileImageFactory.CreateRandomJpeg();
-        var metadata = ValidMetadata() with { CapturedAt = now.AddDays(-8) };
+        var metadata = ValidMetadata() with { CapturedAt = new DateTimeOffset(now.AddDays(-8), TimeSpan.Zero) };
 
         // Act
         var result = gate.Validate(bytes, JpegContentType, metadata);
@@ -148,7 +148,7 @@ public class UavTileQualityGateTests
         var now = new DateTime(2026, 5, 11, 12, 0, 0, DateTimeKind.Utc);
         var gate = BuildGate(timeProvider: new FixedTimeProvider(now));
         var bytes = UavTileImageFactory.CreateRandomJpeg();
-        var metadata = ValidMetadata() with { CapturedAt = now.AddSeconds(20) };
+        var metadata = ValidMetadata() with { CapturedAt = new DateTimeOffset(now.AddSeconds(20), TimeSpan.Zero) };
 
         // Act
         var result = gate.Validate(bytes, JpegContentType, metadata);
@@ -216,7 +216,7 @@ public class UavTileQualityGateTests
         Longitude = 37.647063,
         TileZoom = 18,
         TileSizeMeters = 200.0,
-        CapturedAt = new DateTime(2026, 5, 11, 11, 30, 0, DateTimeKind.Utc),
+        CapturedAt = new DateTimeOffset(2026, 5, 11, 11, 30, 0, TimeSpan.Zero),
     };
 
     private sealed class FixedTimeProvider : TimeProvider

SatelliteProvider.Tests/UavTileUploadHandlerTests.cs

@@ -275,7 +275,7 @@ public class UavTileUploadHandlerTests : IDisposable
         Longitude = 37.647063,
         TileZoom = 18,
         TileSizeMeters = 200.0,
-        CapturedAt = new DateTime(2026, 5, 11, 11, 30, 0, DateTimeKind.Utc),
+        CapturedAt = new DateTimeOffset(2026, 5, 11, 11, 30, 0, TimeSpan.Zero),
     };
 
     private sealed class FixedTimeProvider : TimeProvider

SatelliteProvider.Tests/Validators/UavTileBatchMetadataPayloadValidatorTests.cs

@@ -11,7 +11,7 @@ namespace SatelliteProvider.Tests.Validators;
 public class UavTileBatchMetadataPayloadValidatorTests
 {
     private readonly UavTileBatchMetadataPayloadValidator _validator;
-    private readonly DateTime _now;
+    private readonly DateTimeOffset _now;
 
     public UavTileBatchMetadataPayloadValidatorTests()
     {
@@ -22,7 +22,7 @@ public class UavTileBatchMetadataPayloadValidatorTests
             MaxAgeDays = 7,
             CapturedAtFutureSkewSeconds = 30,
         });
-        _now = new DateTime(2026, 5, 22, 12, 0, 0, DateTimeKind.Utc);
+        _now = new DateTimeOffset(2026, 5, 22, 12, 0, 0, TimeSpan.Zero);
         _validator = new UavTileBatchMetadataPayloadValidator(config, new FixedTimeProvider(_now));
     }
 
@@ -96,8 +96,8 @@ public class UavTileBatchMetadataPayloadValidatorTests
 
     private sealed class FixedTimeProvider : TimeProvider
     {
-        private readonly DateTime _utcNow;
-        public FixedTimeProvider(DateTime utcNow) => _utcNow = utcNow;
-        public override DateTimeOffset GetUtcNow() => new(_utcNow, TimeSpan.Zero);
+        private readonly DateTimeOffset _utcNow;
+        public FixedTimeProvider(DateTimeOffset utcNow) => _utcNow = utcNow;
+        public override DateTimeOffset GetUtcNow() => _utcNow;
     }
 }

SatelliteProvider.Tests/Validators/UavTileMetadataValidatorTests.cs

@@ -13,7 +13,7 @@ namespace SatelliteProvider.Tests.Validators;
 public class UavTileMetadataValidatorTests
 {
     private readonly UavTileMetadataValidator _validator;
-    private readonly DateTime _now;
+    private readonly DateTimeOffset _now;
 
     public UavTileMetadataValidatorTests()
     {
@@ -23,7 +23,7 @@ public class UavTileMetadataValidatorTests
             MaxAgeDays = 7,
             CapturedAtFutureSkewSeconds = 30,
         });
-        _now = new DateTime(2026, 5, 22, 12, 0, 0, DateTimeKind.Utc);
+        _now = new DateTimeOffset(2026, 5, 22, 12, 0, 0, TimeSpan.Zero);
         _validator = new UavTileMetadataValidator(config, new FixedTimeProvider(_now));
     }
 
@@ -32,12 +32,12 @@ public class UavTileMetadataValidatorTests
     // consumer appears, promote to SatelliteProvider.TestSupport.
     private sealed class FixedTimeProvider : TimeProvider
     {
-        private readonly DateTime _utcNow;
-        public FixedTimeProvider(DateTime utcNow) => _utcNow = utcNow;
-        public override DateTimeOffset GetUtcNow() => new(_utcNow, TimeSpan.Zero);
+        private readonly DateTimeOffset _utcNow;
+        public FixedTimeProvider(DateTimeOffset utcNow) => _utcNow = utcNow;
+        public override DateTimeOffset GetUtcNow() => _utcNow;
     }
 
-    private static UavTileMetadata ValidMetadata(DateTime capturedAt) => new()
+    private static UavTileMetadata ValidMetadata(DateTimeOffset capturedAt) => new()
     {
         Latitude = 50.10,
         Longitude = 36.10,