[AZ-376] [AZ-378] [AZ-379] [AZ-380] Repo cleanup: dead code, logger discipline, ColumnList consts

Batch 23 of refactor 03-code-quality-refactoring (4 tasks, 5 SP):

- AZ-376 (C23): Delete unused FindExistingTileAsync from
  ITileRepository / TileRepository. No callers; method also took the
  obsolete `version` arg removed by C06/AZ-357.
- AZ-378 (C25): Repository _logger discipline.
  TileRepository.GetTilesByRegionAsync now emits LogWarning when the
  query exceeds SlowQueryThresholdMs (500 ms). RegionRepository and
  RouteRepository drop the unused ILogger<TRepo> field, parameter, and
  using; Program.cs DI registrations updated.
- AZ-379 (C26): Extract `private const string ColumnList` per repo
  (TileRepository, RegionRepository, RouteRepository); SELECTs use
  $@"SELECT {ColumnList} FROM ..." (C# 10+ const interpolation).
  INSERT/UPDATE/DELETE unchanged; route_points single-site SELECT left
  inline.
- AZ-380 (C27): Delete dead alias GeoUtils.CalculatePolygonDiagonalDistance.

Tests: +9 new (RepositoryRefactorTests x8, GeoUtilsRefactorTests x1)
covering each AC via reflection / file-content assertions; pattern
mirrors ToolingConfigurationTests (b22) and AcceptanceCriteriaRT2Tests
(b19). Unit suite 181 -> 190, all green. dotnet format clean.

Code review: PASS_WITH_WARNINGS (3 Low findings, all informational or
out-of-scope for this batch). See
_docs/03_implementation/reviews/batch_23_review.md.

Cumulative review counter 2/3; next K=3 review fires after batch 24.

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

SatelliteProvider.DataAccess/Repositories/RegionRepository.cs

@@ -1,5 +1,4 @@
 using Dapper;
-using Microsoft.Extensions.Logging;
 using Npgsql;
 using SatelliteProvider.Common.Enums;
 using SatelliteProvider.DataAccess.Models;
@@ -8,26 +7,26 @@ namespace SatelliteProvider.DataAccess.Repositories;
 
 public class RegionRepository : IRegionRepository
 {
-    private readonly string _connectionString;
-    private readonly ILogger<RegionRepository> _logger;
+    private const string ColumnList = @"id, latitude, longitude, size_meters as SizeMeters,
+                   zoom_level as ZoomLevel, status,
+                   csv_file_path as CsvFilePath, summary_file_path as SummaryFilePath,
+                   tiles_downloaded as TilesDownloaded, tiles_reused as TilesReused,
+                   stitch_tiles as StitchTiles,
+                   created_at as CreatedAt, updated_at as UpdatedAt";
 
-    public RegionRepository(string connectionString, ILogger<RegionRepository> logger)
+    private readonly string _connectionString;
+
+    public RegionRepository(string connectionString)
     {
         _connectionString = connectionString;
-        _logger = logger;
     }
 
     public async Task<RegionEntity?> GetByIdAsync(Guid id)
     {
         using var connection = new NpgsqlConnection(_connectionString);
-        const string sql = @"
-            SELECT id, latitude, longitude, size_meters as SizeMeters, 
-                   zoom_level as ZoomLevel, status, 
-                   csv_file_path as CsvFilePath, summary_file_path as SummaryFilePath,
-                   tiles_downloaded as TilesDownloaded, tiles_reused as TilesReused,
-                   stitch_tiles as StitchTiles,
-                   created_at as CreatedAt, updated_at as UpdatedAt
-            FROM regions 
+        const string sql = $@"
+            SELECT {ColumnList}
+            FROM regions
             WHERE id = @Id";
 
         var region = await connection.QuerySingleOrDefaultAsync<RegionEntity>(sql, new { Id = id });
@@ -37,14 +36,9 @@ public class RegionRepository : IRegionRepository
     public async Task<IEnumerable<RegionEntity>> GetByStatusAsync(RegionStatus status)
     {
         using var connection = new NpgsqlConnection(_connectionString);
-        const string sql = @"
-            SELECT id, latitude, longitude, size_meters as SizeMeters, 
-                   zoom_level as ZoomLevel, status, 
-                   csv_file_path as CsvFilePath, summary_file_path as SummaryFilePath,
-                   tiles_downloaded as TilesDownloaded, tiles_reused as TilesReused,
-                   stitch_tiles as StitchTiles,
-                   created_at as CreatedAt, updated_at as UpdatedAt
-            FROM regions 
+        const string sql = $@"
+            SELECT {ColumnList}
+            FROM regions
             WHERE status = @Status
             ORDER BY created_at ASC";
 
@@ -96,4 +90,3 @@ public class RegionRepository : IRegionRepository
         return await connection.ExecuteAsync(sql, new { Id = id });
     }
 }
-