[AZ-371] Refactor C18: magic numbers to ProcessingConfig/MapConfig

Promotes 8 operational levers into config keys with defaults that match
the prior source literals byte-for-byte:
  ProcessingConfig: RegionProcessingTimeoutSeconds (300),
  RouteProcessingPollIntervalSeconds (5),
  MaxRoutePointSpacingMeters (200), LatLonTolerance (0.0001).
  MapConfig: TileSizePixels (256), AllowedZoomLevels ([15..19]),
  RetryBaseDelaySeconds (1), RetryMaxDelaySeconds (30).

Sites updated: RegionService, RouteProcessingService,
RoutePointGraphBuilder, RouteValidator, RouteService 4-arg ctor,
RouteImageRenderer, GoogleMapsDownloaderV2, TileService. Closes LF-2 by
forwarding HttpContext.RequestAborted from GetTileByLatLon into the
downloader. appsettings.json gains the 8 new keys at default values.

Tests: 141 / 141 unit + 5 / 5 smoke green. New ConfigDefaultsTests pins
defaults to original literals; new TileService unit test asserts CT
identity from caller to downloader (AZ-371 AC-3).

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

SatelliteProvider.Services.RouteManagement/RouteService.cs

@@ -1,4 +1,6 @@
 using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using SatelliteProvider.Common.Configs;
 using SatelliteProvider.Common.DTO;
 using SatelliteProvider.Common.Interfaces;
 using SatelliteProvider.DataAccess.Models;
@@ -19,10 +21,11 @@ public class RouteService : IRouteService
     public RouteService(
         IRouteRepository routeRepository,
         IRegionService regionService,
+        IOptions<ProcessingConfig> processingConfig,
         ILogger<RouteService> logger)
         : this(routeRepository, regionService, logger,
-              new RouteValidator(),
-              new RoutePointGraphBuilder(),
+              new RouteValidator(processingConfig),
+              new RoutePointGraphBuilder(processingConfig),
               new GeofenceGridCalculator(),
               new RouteResponseMapper())
     {