[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>

_docs/02_tasks/_dependencies_table.md

@@ -30,9 +30,9 @@ Roadmap: `_docs/04_refactoring/03-code-quality-refactoring/analysis/refactoring_
 
 | Task | C-ID | Title | Phase | Depends On | Points | Status |
 |------|------|-------|-------|-----------|--------|--------|
-| AZ-351 | C01 | Fix null logger to DatabaseMigrator | 1 | — | 2 | To Do |
-| AZ-352 | C02 | Replace empty catch in ExtractTileCoordinatesFromFilename | 1 | — | 2 | To Do |
-| AZ-363 | C10 | Delete write-only counters in RegionRequestQueue | 1 | — | 1 | To Do |
+| AZ-351 | C01 | Fix null logger to DatabaseMigrator | 1 | — | 2 | Done (In Testing) |
+| AZ-352 | C02 | Replace empty catch in ExtractTileCoordinatesFromFilename | 1 | — | 2 | Done (In Testing) |
+| AZ-363 | C10 | Delete write-only counters in RegionRequestQueue | 1 | — | 1 | Done (In Testing) |
 | AZ-356 | C05 | Stub endpoints return 501 | 1 | — | 2 | To Do |
 | AZ-354 | C04 | Strict CORS by default | 1 | — | 2 | To Do |
 | AZ-353 | C03 | Sanitize 5xx responses via IExceptionHandler | 1 | — | 3 | To Do |