[AZ-812] Region API: rename Latitude/Longitude → Lat/Lon (OSM convention)

Mirror of AZ-794 (inventory z/x/y rename). RequestRegionRequest.cs renames C#
props Latitude→Lat / Longitude→Lon and adds [JsonPropertyName("lat"/"lon")] so
the wire format is unambiguous under the AZ-795 strict-parsing stack
(UnmappedMemberHandling.Disallow → legacy {"latitude":..,"longitude":..} now
returns HTTP 400 instead of silently coercing).

Updates all in-repo consumers: API handler (Program.cs), integration tests
(Models.cs, RegionTests.cs, IdempotentPostTests.cs, SecurityTests.cs), the
performance harness (run-performance-tests.sh PT-03/04/05/07), and module
docs (common_dtos.md, api_program.md; system-flows.md F2 already used
lat/lon). New RegionFieldRenameTests.cs covers AC-4 both directions (new
format → 200, legacy format → 400). Smoke green; no regressions.

region-request.md contract doc not bumped here — AZ-808 publishes v1.0.0
directly with the post-rename names per AZ-812 coordination clause.

Batch 01 of cycle 8. PASS_WITH_WARNINGS (one Low DRY finding for follow-up
test-helper consolidation; details in
_docs/03_implementation/reviews/batch_01_cycle8_review.md).

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

SatelliteProvider.IntegrationTests/IdempotentPostTests.cs

@@ -30,8 +30,8 @@ public static class IdempotentPostTests
         var body = JsonSerializer.Serialize(new
         {
             id = regionId,
-            latitude = 47.4617,
-            longitude = 37.6470,
+            lat = 47.4617,
+            lon = 37.6470,
             sizeMeters = 200,
             zoomLevel = 18,
             stitchTiles = false,

SatelliteProvider.IntegrationTests/Models.cs

@@ -17,8 +17,13 @@ public record DownloadTileResponse
 public record RequestRegionRequest
 {
     public Guid Id { get; set; }
-    public double Latitude { get; set; }
-    public double Longitude { get; set; }
+
+    [System.Text.Json.Serialization.JsonPropertyName("lat")]
+    public double Lat { get; set; }
+
+    [System.Text.Json.Serialization.JsonPropertyName("lon")]
+    public double Lon { get; set; }
+
     public double SizeMeters { get; set; }
     public int ZoomLevel { get; set; }
     public bool StitchTiles { get; set; } = false;

SatelliteProvider.IntegrationTests/Program.cs

@@ -140,6 +140,7 @@ class Program
         await IdempotentPostTests.RunAll(httpClient);
         await TileInventoryTests.RunAll(httpClient);
         await TileInventoryValidationTests.RunAll(httpClient);
+        await RegionFieldRenameTests.RunAll(httpClient);
         await LeafletPathIndexOnlyTests.RunAll(connectionString);
         await MigrationTests.RunAll();
     }
@@ -164,6 +165,7 @@ class Program
         await IdempotentPostTests.RunAll(httpClient);
         await TileInventoryTests.RunAll(httpClient);
         await TileInventoryValidationTests.RunAll(httpClient);
+        await RegionFieldRenameTests.RunAll(httpClient);
         await LeafletPathIndexOnlyTests.RunAll(connectionString);
         await MigrationTests.RunAll();
     }

SatelliteProvider.IntegrationTests/RegionFieldRenameTests.cs

@@ -0,0 +1,111 @@
+using System.Net.Http.Json;
+using System.Text;
+using System.Text.Json;
+
+namespace SatelliteProvider.IntegrationTests;
+
+// AZ-812: wire-format rename for POST /api/satellite/request.
+// `RequestRegionRequest` now uses `lat`/`lon` (OSM convention) on the wire,
+// replacing the previous verbose `latitude`/`longitude`. The strict-parsing
+// infrastructure landed by AZ-795 (UnmappedMemberHandling.Disallow +
+// GlobalExceptionHandler) means the old wire format must now be rejected
+// explicitly, not silently coerced. AC-4 from the AZ-812 task spec.
+public static class RegionFieldRenameTests
+{
+    private const string RegionPath = "/api/satellite/request";
+
+    public static async Task RunAll(HttpClient httpClient)
+    {
+        RouteTestHelpers.PrintTestHeader("Test: Region endpoint OSM field-name rename (AZ-812)");
+
+        await NewLatLonFormat_Returns200(httpClient);
+        await OldLatitudeLongitudeFormat_Returns400(httpClient);
+
+        Console.WriteLine("✓ Region field-rename tests: PASSED");
+    }
+
+    private static async Task NewLatLonFormat_Returns200(HttpClient httpClient)
+    {
+        Console.WriteLine();
+        Console.WriteLine("AZ-812 AC-4 (positive): new {lat,lon} wire format → HTTP 200");
+
+        // Arrange
+        var regionId = Guid.NewGuid();
+        var body = $"{{\"id\":\"{regionId}\",\"lat\":47.461747,\"lon\":37.647063,\"sizeMeters\":200,\"zoomLevel\":18,\"stitchTiles\":false}}";
+
+        // Act
+        var response = await PostJsonAsync(httpClient, body);
+        var status = (int)response.StatusCode;
+        var responseBody = await response.Content.ReadAsStringAsync();
+
+        // Assert
+        if (status != 200)
+        {
+            throw new Exception($"AZ-812 AC-4 positive: expected HTTP 200 for {{lat,lon}} body, got {status}. Body: {responseBody}");
+        }
+
+        Console.WriteLine("  ✓ {lat,lon} body accepted with HTTP 200");
+    }
+
+    private static async Task OldLatitudeLongitudeFormat_Returns400(HttpClient httpClient)
+    {
+        Console.WriteLine();
+        Console.WriteLine("AZ-812 AC-4 (negative): legacy {latitude,longitude} wire format → HTTP 400 (UnmappedMemberHandling.Disallow)");
+
+        // Arrange — exact pre-AZ-812 wire format; must now fail explicitly instead
+        // of silently mapping to the renamed Lat/Lon properties.
+        var regionId = Guid.NewGuid();
+        var body = $"{{\"id\":\"{regionId}\",\"latitude\":47.461747,\"longitude\":37.647063,\"sizeMeters\":200,\"zoomLevel\":18,\"stitchTiles\":false}}";
+
+        // Act
+        var response = await PostJsonAsync(httpClient, body);
+        var problem = await ProblemDetailsAssertions.ReadProblemDetailsAsync(response, "AZ-812 legacy field names");
+
+        // Assert
+        ProblemDetailsAssertions.AssertValidationProblem(problem, expectedStatus: 400, label: "AZ-812 legacy field names");
+        AssertErrorsContainsMention(problem, expectedMention: "latitude", label: "AZ-812 legacy field names");
+
+        Console.WriteLine("  ✓ Legacy {latitude,longitude} body rejected with HTTP 400; errors map names the unknown field");
+    }
+
+    private static Task<HttpResponseMessage> PostJsonAsync(HttpClient httpClient, string body)
+    {
+        var content = new StringContent(body, Encoding.UTF8, "application/json");
+        return httpClient.PostAsync(RegionPath, content);
+    }
+
+    private static void AssertErrorsContainsMention(JsonElement problem, string expectedMention, string label)
+    {
+        if (!problem.TryGetProperty("errors", out var errorsEl) || errorsEl.ValueKind != JsonValueKind.Object)
+        {
+            throw new Exception($"{label}: expected 'errors' object in ProblemDetails body.");
+        }
+
+        var found = false;
+        foreach (var prop in errorsEl.EnumerateObject())
+        {
+            if (prop.Name.Contains(expectedMention, StringComparison.OrdinalIgnoreCase))
+            {
+                found = true;
+                break;
+            }
+
+            foreach (var msg in prop.Value.EnumerateArray())
+            {
+                if (msg.GetString()?.Contains(expectedMention, StringComparison.OrdinalIgnoreCase) == true)
+                {
+                    found = true;
+                    break;
+                }
+            }
+
+            if (found) break;
+        }
+
+        if (!found)
+        {
+            var paths = string.Join(", ", errorsEl.EnumerateObject().Select(p => p.Name));
+            throw new Exception($"{label}: expected '{expectedMention}' to appear in errors keys or messages. Available paths: {paths}.");
+        }
+    }
+}

SatelliteProvider.IntegrationTests/RegionTests.cs

@@ -84,8 +84,8 @@ public static class RegionTests
         var requestRegion = new RequestRegionRequest
         {
             Id = regionId,
-            Latitude = latitude,
-            Longitude = longitude,
+            Lat = latitude,
+            Lon = longitude,
             SizeMeters = sizeMeters,
             ZoomLevel = zoomLevel,
             StitchTiles = stitchTiles

SatelliteProvider.IntegrationTests/SecurityTests.cs

@@ -66,7 +66,7 @@ public static class SecurityTests
         Console.WriteLine("SEC-03: Oversized region request (sizeMeters beyond allowed cap)");
 
         var regionId = Guid.NewGuid();
-        var body = $"{{\"id\":\"{regionId}\",\"latitude\":47.461747,\"longitude\":37.647063,\"sizeMeters\":1000000,\"zoomLevel\":18,\"stitchTiles\":false}}";
+        var body = $"{{\"id\":\"{regionId}\",\"lat\":47.461747,\"lon\":37.647063,\"sizeMeters\":1000000,\"zoomLevel\":18,\"stitchTiles\":false}}";
         var content = new StringContent(body, Encoding.UTF8, "application/json");
         var response = await httpClient.PostAsync("/api/satellite/request", content);
         var status = (int)response.StatusCode;