[AZ-351][AZ-352][AZ-363] Refactor 03 batch 1: critical defensive fixes

AZ-351: Resolve ILogger<DatabaseMigrator> directly from DI in
Program.cs instead of casting ILogger<Program> (which always
returned null). Migrator now logs through Serilog at startup.

AZ-352: Drop empty catch in
RouteProcessingService.ExtractTileCoordinatesFromFilename. Convert
the method from private static to internal instance so it can use
the existing _logger (per coderule: side-effecting code must not be
static). Add typed null-guard via ArgumentNullException.ThrowIfNull
so unexpected exceptions propagate. Adds InternalsVisibleTo on the
RouteManagement csproj for SatelliteProvider.Tests, plus 4 unit
tests in RouteProcessingServiceTests.cs covering AC-1 (valid /
malformed / non-numeric) and AC-2 (null path propagation).

AZ-363: Delete _totalEnqueued / _totalDequeued fields and the two
non-atomic ++ writes in RegionRequestQueue. Fields were write-only
dead code and a thread-safety hazard.

Tests: 44/44 unit + 5/5 smoke (scripts/run-tests.sh --smoke).
Code review verdict: PASS, 0 findings, 0 auto-fix attempts.
Batch report: _docs/03_implementation/batch_07_report.md.

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

SatelliteProvider.Services.RouteManagement/RouteProcessingService.cs

@@ -607,25 +607,23 @@ public class RouteProcessingService : BackgroundService
         return earthRadiusMeters * c;
     }
 
-    private static (int TileX, int TileY) ExtractTileCoordinatesFromFilename(string filePath)
+    internal (int TileX, int TileY) ExtractTileCoordinatesFromFilename(string filePath)
     {
-        try
+        ArgumentNullException.ThrowIfNull(filePath);
+
+        var filename = Path.GetFileNameWithoutExtension(filePath);
+        var parts = filename.Split('_');
+
+        if (parts.Length >= 4 && parts[0] == "tile" &&
+            int.TryParse(parts[2], out var tileX) &&
+            int.TryParse(parts[3], out var tileY))
         {
-            var filename = Path.GetFileNameWithoutExtension(filePath);
-            var parts = filename.Split('_');
-            
-            if (parts.Length >= 4 && parts[0] == "tile")
-            {
-                if (int.TryParse(parts[2], out var tileX) && int.TryParse(parts[3], out var tileY))
-                {
-                    return (tileX, tileY);
-                }
-            }
+            return (tileX, tileY);
         }
-        catch
-        {
-        }
-        
+
+        _logger.LogWarning(
+            "Could not extract tile coordinates from filename {FilePath}; expected pattern tile_<timestamp>_<x>_<y>",
+            filePath);
         return (-1, -1);
     }
 

SatelliteProvider.Services.RouteManagement/SatelliteProvider.Services.RouteManagement.csproj

@@ -19,4 +19,8 @@
       <ProjectReference Include="..\SatelliteProvider.DataAccess\SatelliteProvider.DataAccess.csproj" />
     </ItemGroup>
 
+    <ItemGroup>
+      <InternalsVisibleTo Include="SatelliteProvider.Tests" />
+    </ItemGroup>
+
 </Project>