[AZ-284] Autodev baseline + testability refactor

Phase A baseline outputs from /autodev (Steps 1-5):
- Problem & solution docs (_docs/00_problem, _docs/01_solution)
- Codebase documentation (_docs/02_document) incl. architecture,
  module-layout, glossary, system-flows, baseline compliance scan
- Test specs (blackbox, performance, resilience, security, resource,
  traceability matrix)
- Test task decomposition (_docs/02_tasks/todo): AZ-285..AZ-290
- Testability refactor (_docs/04_refactoring/01-testability-refactoring):
  - TC-01 Move DownloadedTileInfoV2 + new ExistingTileInfo to Common.DTO
  - TC-02 Replace dead ISatelliteDownloader API with real signatures
  - TC-03 GoogleMapsDownloaderV2 implements ISatelliteDownloader
  - TC-04 TileService depends on ISatelliteDownloader (mockable)
  - TC-05 DI + endpoints use ISatelliteDownloader
- Test runner scripts (scripts/run-tests.sh, run-performance-tests.sh)
- Autodev state pointer (_docs/_autodev_state.md)

Prepares the codebase for AZ-285..AZ-290 unit/integration test work.

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

SatelliteProvider.Services/GoogleMapsDownloaderV2.cs

@@ -5,18 +5,17 @@ using Microsoft.Extensions.Options;
 using Newtonsoft.Json;
 using SatelliteProvider.Common.Configs;
 using SatelliteProvider.Common.DTO;
+using SatelliteProvider.Common.Interfaces;
 using SatelliteProvider.Common.Utils;
 
 namespace SatelliteProvider.Services;
 
-public record DownloadedTileInfoV2(int X, int Y, int ZoomLevel, double CenterLatitude, double CenterLongitude, string FilePath, double TileSizeMeters);
-
 public class RateLimitException : Exception
 {
     public RateLimitException(string message) : base(message) { }
 }
 
-public class GoogleMapsDownloaderV2
+public class GoogleMapsDownloaderV2 : ISatelliteDownloader
 {
     private const string TILE_URL_TEMPLATE = "https://mt{0}.google.com/vt/lyrs=s&x={1}&y={2}&z={3}&token={4}";
     private const string USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.0.0 Safari/537.36";
@@ -231,7 +230,7 @@ public class GoogleMapsDownloaderV2
         GeoPoint centerGeoPoint, 
         double radiusM, 
         int zoomLevel, 
-        IEnumerable<DataAccess.Models.TileEntity> existingTiles,
+        IEnumerable<ExistingTileInfo> existingTiles,
         CancellationToken token = default)
     {
         if (!ALLOWED_ZOOM_LEVELS.Contains(zoomLevel))