[AZ-375] [AZ-377] HashSet tile lookup + consolidate Earth constants

Batch 24 of 03-code-quality-refactoring run; closes the run.

AZ-375 (C22): GoogleMapsDownloaderV2.DownloadTilesGridAsync now
builds a HashSet<(int X, int Y, int Z)> once from existingTiles
and tests Contains((x, y, zoomLevel)) per cell. Removes the per-cell
FirstOrDefault tolerance scan and the unused _processingConfig
.LatLonTolerance reference at this site.

AZ-377 (C24): promote Earth + tile-pixel constants to a single
home. GeoUtils now exposes EarthRadiusMeters, EarthEquatorial
CircumferenceMeters, MetersPerDegreeLatitude as public const.
MapConfig adds DefaultTileSizePixels (const) wired as the
TileSizePixels property default. TileRepository and Google
MapsDownloaderV2 read those constants instead of duplicating
the literals 6378137, 40075016.686, 111000.0, and 256.

Tests: +6 new (DownloaderRefactorTests, extended GeoUtils
RefactorTests). 200/200 unit tests pass.

Cumulative K=3 review (batches 22-24): PASS_WITH_WARNINGS,
4 Low findings only — see
_docs/03_implementation/reviews/cumulative_review_22-24.md.

Tooling fix: scripts/run-tests.sh --unit-only path now restores
before testing (was failing on SixLabors resolution in clean
container). Stripped stray BOM from MapConfig.cs to satisfy the
.editorconfig charset gate.

Updates _dependencies_table.md to reflect all 27 03-code-quality-
refactoring tasks done; updates _autodev_state.md to refactor
phase 5 (test-sync).

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

_docs/03_implementation/batch_24_report.md

@@ -0,0 +1,102 @@
+# Batch Report
+
+**Batch**: 24
+**Tasks**: AZ-375 (C22 — HashSet existing-tile lookup), AZ-377 (C24 — consolidate Earth + tile-pixel constants)
+**Date**: 2026-05-11
+**Run**: `03-code-quality-refactoring`
+**Cycle**: 1
+
+## Task Results
+
+| Task | Status | Files Modified | Tests | AC Coverage | Issues |
+|------|--------|----------------|-------|-------------|--------|
+| AZ-375_refactor_on_existing_tile_lookup | Done | 1 (`GoogleMapsDownloaderV2.cs`) | 1 new (DownloaderRefactorTests AZ375_AC1) | 3/3 | None |
+| AZ-377_refactor_consolidate_earth_constants | Done | 4 (`GeoUtils.cs`, `MapConfig.cs`, `TileRepository.cs`, `GoogleMapsDownloaderV2.cs`) | 5 new (DownloaderRefactorTests + GeoUtilsRefactorTests AZ377_AC1/AC2) | 3/3 | F1 in cumulative review (Low / Architecture documentation drift, non-blocking) |
+
+Total: 4 source files modified + 1 new test file (`DownloaderRefactorTests.cs`) + 1 extended test file (`GeoUtilsRefactorTests.cs`) + 6 new test cases (5 for AZ-377 across both files, 1 for AZ-375).
+
+## Changes
+
+### AZ-375 — O(N) existing-tile lookup via HashSet
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`:
+  - Removed the per-cell `existingTiles.FirstOrDefault(t => Math.Abs(...) < tolerance && ... )` linear scan.
+  - Added a one-time `HashSet<(int X, int Y, int Z)>` build keyed on the integer `(TileX, TileY, Zoom)` derived via the same `GeoUtils.WorldToTilePos` formula used to write the tiles.
+  - Inner loop now does `existingTileKeys.Contains((x, y, zoomLevel))` — O(1) per cell.
+  - `_processingConfig.LatLonTolerance` is no longer referenced at this site (tolerance was redundant since tile coordinates at a fixed zoom are integers).
+- The other tolerance use site (`RouteService.cs:154` geofence polygon check) is untouched.
+
+### AZ-377 — consolidate Earth-geometry + tile-pixel constants
+- `SatelliteProvider.Common/Utils/GeoUtils.cs`:
+  - Promoted `EARTH_RADIUS = 6378137` to `public const double EarthRadiusMeters = 6378137d`.
+  - Added `public const double EarthEquatorialCircumferenceMeters = 40075016.686d`.
+  - Added `public const double MetersPerDegreeLatitude = 111000d`.
+  - Updated all internal usages in `GeoUtils` (Haversine, GoDirection, GetBoundingBox).
+- `SatelliteProvider.Common/Configs/MapConfig.cs`:
+  - Added `public const int DefaultTileSizePixels = 256`.
+  - `TileSizePixels` property default now references the const.
+  - Added inline doc comment explaining why both surfaces exist (DataAccess cannot inject `IOptions<MapConfig>` from a Repository ctor).
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`:
+  - `CalculateTileSizeInMeters` now reads `GeoUtils.EarthEquatorialCircumferenceMeters` instead of a local `EARTH_CIRCUMFERENCE_METERS` const.
+- `SatelliteProvider.DataAccess/Repositories/TileRepository.cs`:
+  - Added `using SatelliteProvider.Common.Configs;` and `using SatelliteProvider.Common.Utils;`.
+  - `GetTilesByRegionAsync` now uses `GeoUtils.EarthEquatorialCircumferenceMeters`, `GeoUtils.MetersPerDegreeLatitude`, and `MapConfig.DefaultTileSizePixels` — all local literals (`EARTH_CIRCUMFERENCE_METERS`, `TILE_SIZE_PIXELS`, two `111000.0` occurrences) removed.
+
+### Test additions
+- `SatelliteProvider.Tests/DownloaderRefactorTests.cs` (new):
+  - `GoogleMapsDownloaderV2_UsesHashSetForExistingTileLookup_AZ375_AC1` — file-content assertion that the FirstOrDefault scan and `_processingConfig.LatLonTolerance` are gone and replaced by a typed HashSet + `Contains` call.
+  - `GoogleMapsDownloaderV2_UsesGeoUtilsCircumferenceConstant_AZ377_AC1` — verifies the downloader routes through `GeoUtils.EarthEquatorialCircumferenceMeters`.
+  - `TileRepository_UsesGeoUtilsAndMapConfigConstants_AZ377_AC1` — verifies the repository uses the `Common` constants and no local Earth literals remain.
+  - `GeoUtils_IsTheSoleHolderOfRawEarthLiterals_AZ377_AC1` — pins `GeoUtils.cs` as the single declaration site.
+  - `HaversineDistance_WithTinyDelta_UsesEarthRadiusConstantConsistently_AZ377_AC2` — numerical equivalence check (recomputes the expected value from the same constant and asserts byte-level identity).
+- `SatelliteProvider.Tests/GeoUtilsRefactorTests.cs` (extended):
+  - `GeoUtils_ExposesEarthConstantsAsPublicConst_AZ377_AC1` — `[Theory]` with three inline data rows; reflection check for `IsLiteral`, type, and value.
+  - `MapConfig_ExposesDefaultTileSizePixelsConst_AZ377_AC1` — verifies the const exists and the property default still resolves to it.
+  - `GeoUtils_HaversineProducesIdenticalResultAfterConstantRename_AZ377_AC2` — quick value-pin sanity check.
+
+### Tooling fix discovered during batch
+- `scripts/run-tests.sh` `--unit-only` path was running `dotnet test --no-restore` without an explicit `dotnet restore` first; this caused `SixLabors.ImageSharp` resolution to fail in a clean container. Wrapped the command with `sh -c "dotnet restore ... && dotnet test --no-restore ..."` to mirror the `--full` path. Pure infrastructure fix — not a refactor task.
+- Stripped a stray UTF-8 BOM from `MapConfig.cs` introduced during the AZ-377 edits, to satisfy the `dotnet format whitespace --verify-no-changes` gate (`charset = utf-8` in `.editorconfig`).
+
+## Test Results
+
+`scripts/run-tests.sh --unit-only`:
+- Format gate: PASS
+- Unit tests: 200/200 PASS (190 prior + 10 new)
+- Coverage: written to `./TestResults/`
+
+## Cumulative Review (K=3, batches 22-24)
+
+Triggered after batch 24. Verdict: **PASS_WITH_WARNINGS**.
+
+- 0 Critical, 0 High, 0 Medium, 4 Low findings.
+- Report: `_docs/03_implementation/reviews/cumulative_review_22-24.md`.
+- One Low / Architecture finding (F1) flags a pre-existing documentation drift around DataAccess→Common dependency (the project reference was already there; AZ-377 widens the surface from `Common.Enums` to also include `Common.Configs` and `Common.Utils`). Recommended follow-up: refresh `module-layout.md` and the architecture baseline F5 entry. Not blocking.
+
+## Files Modified
+
+Production:
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`
+- `SatelliteProvider.Common/Utils/GeoUtils.cs`
+- `SatelliteProvider.Common/Configs/MapConfig.cs`
+- `SatelliteProvider.DataAccess/Repositories/TileRepository.cs`
+
+Tests:
+- `SatelliteProvider.Tests/DownloaderRefactorTests.cs` (new)
+- `SatelliteProvider.Tests/GeoUtilsRefactorTests.cs` (extended)
+
+Tooling:
+- `scripts/run-tests.sh` (unit-only path now restores before testing)
+
+Docs / state:
+- `_docs/02_tasks/done/AZ-375_refactor_on_existing_tile_lookup.md` (moved from todo)
+- `_docs/02_tasks/done/AZ-377_refactor_consolidate_earth_constants.md` (moved from todo)
+- `_docs/03_implementation/batch_24_report.md` (this file)
+- `_docs/03_implementation/reviews/cumulative_review_22-24.md`
+- `_docs/_autodev_state.md`
+
+## Status
+
+- Both batch-24 tasks DONE.
+- Batches 22-24 cumulative review COMPLETE; verdict PASS_WITH_WARNINGS.
+- 03-code-quality-refactoring run: 6/6 tasks done (AZ-372, AZ-375, AZ-376, AZ-377, AZ-378, AZ-379, AZ-380 — note: 7 tracker IDs because AZ-372 covers tooling C19 separately from the C-prefixed change items).
+- Refactoring epic (AZ-309 / AZ-350) progress: see traceability table.