[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>

_docs/02_document/tests/environment.md

@@ -0,0 +1,49 @@
+# Test Environment
+
+## Infrastructure
+
+| Component | Technology | Configuration |
+|-----------|-----------|---------------|
+| System Under Test | SatelliteProvider.Api (Docker container) | ASPNETCORE_ENVIRONMENT=Development |
+| Database | PostgreSQL 16 (Docker container) | Fresh DB per test run (migrations auto-applied) |
+| Test Runner | Custom console app (SatelliteProvider.IntegrationTests) | Docker container on same network |
+| Orchestration | docker-compose.tests.yml | Waits for API health before starting tests |
+
+## Network Topology
+
+```
+[Test Runner] --HTTP--> [API :8080] --TCP--> [PostgreSQL :5432]
+                              |
+                              +--HTTPS--> [Google Maps] (external, real)
+```
+
+## External Dependencies
+
+| Dependency | Strategy | Notes |
+|------------|----------|-------|
+| Google Maps tile server | Real (live) | Integration tests use real downloads; requires GOOGLE_MAPS_API_KEY |
+| PostgreSQL | Real (containerized) | Fresh database each run via migrations |
+| File system | Real (Docker volume) | ./tiles, ./ready, ./logs mounted |
+
+## Environment Variables
+
+| Variable | Value | Purpose |
+|----------|-------|---------|
+| API_URL | http://api:8080 | Test runner → API connection |
+| ASPNETCORE_ENVIRONMENT | Development | API config mode |
+| ConnectionStrings__DefaultConnection | Host=postgres;Port=5432;... | DB connection |
+| MapConfig__ApiKey | (from host env) | Google Maps auth |
+
+## Test Execution
+
+**Decision**: Docker (no hardware dependencies detected)
+**Hardware dependencies found**: None
+**Execution method**: `docker-compose -f docker-compose.yml -f docker-compose.tests.yml up --build --abort-on-container-exit`
+
+| Property | Value |
+|----------|-------|
+| Execution mode | Sequential (one test at a time) |
+| Timeout per test | 15 minutes (HttpClient timeout) |
+| Polling interval | 2–3 seconds |
+| Max poll attempts | 120–360 (depends on test) |
+| Startup wait | 30 retries × 2s = 60s max |