[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/_autodev_state.md

@@ -8,7 +8,7 @@ status: in_progress
 sub_step:
   phase: 4
   name: execution
-  detail: "RUN_DIR=03-code-quality-refactoring; safety net green (40 unit + 5 smoke); epic AZ-350; 27 tickets (AZ-351..AZ-380, gaps at 355/358/361); /implement starting batch 1"
+  detail: "RUN_DIR=03-code-quality-refactoring; epic AZ-350; batch 7 done (AZ-351/352/363, 5 SP); 24 tickets remaining; next batch 8 = AZ-356/354/353 (Phase 1 part 2, 7 SP, WebApi)"
 retry_count: 0
 cycle: 1
 tracker: jira