[AZ-484] Multi-source tile storage: source + captured_at

Add per-source tile rows to support multi-provider imagery (Google
Maps + future UAV). Migration 013 (transactional) introduces
source/captured_at columns, backfills existing rows to
(source='google_maps', captured_at=created_at), and replaces the
4-column unique index with a 5-column index that includes source.

TileRepository:
- ColumnList includes source + captured_at
- GetByTileCoordinatesAsync returns most-recent row across sources
  (ORDER BY captured_at DESC, updated_at DESC, id DESC)
- GetTilesByRegionAsync uses DISTINCT ON to pick the most-recent
  tile per cell, restoring caller-facing row order
- Insert/Update upsert on the new 5-column conflict key

TileSource enum lives in Common.Enums. Snake_case wire format
(google_maps, uav) is enforced by a focused TileSourceTypeHandler
because the generic ToLowerInvariant pattern would emit
"googlemaps", violating contract v1.0.0.

TileService stamps Source=GoogleMaps + CapturedAt=UtcNow on every
new tile. Tile-storage contract is now frozen at v1.0.0.

AC coverage 7/7. New unit + integration tests cover all ACs;
existing 200 unit + 5 smoke tests preserved.

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

_docs/03_implementation/reviews/batch_25_cycle1_review.md

@@ -0,0 +1,68 @@
+# Code Review Report
+
+**Batch**: 25 (cycle 1)
+**Tasks**: AZ-484 (Multi-source tile storage schema)
+**Date**: 2026-05-11
+**Verdict**: PASS
+
+## Findings
+
+None.
+
+## Phase Summary
+
+### Phase 1 — Context
+Read AZ-484 task spec, `_docs/02_document/contracts/data-access/tile-storage.md` v1.0.0, the existing `_docs/02_document/architecture.md` Architecture Vision section, and the existing `module-layout.md` per-component map. Mapped the 15 changed files to AZ-484 (single-task batch).
+
+### Phase 2 — Spec Compliance
+Walked every AC against code:
+
+| AC | Promise | Validating test |
+|----|---------|-----------------|
+| AC-1 | Per-source coexistence on the same cell | `MultiSourceInsertCoexistsUnderNewIndex_AZ484_AC1` (TEMP), `NewUniqueConstraintIncludesSourceColumn_AZ484_AC1` (live schema) |
+| AC-2 | Most-recent across sources on read | `MostRecentAcrossSourcesSelection_AZ484_AC2` |
+| AC-3 | Same-source UPSERT collapses to one row | `SameSourceUpsertReplacesPreviousRow_AZ484_AC3` |
+| AC-4 | Migration backfill leaves no orphans | `BackfillUpdateAssignsGoogleMapsAndCapturedAt_AZ484_AC4` (TEMP simulation of the migration UPDATE) |
+| AC-5 | Google Maps path stamps Source + CapturedAt | `BuildTileEntity_SetsGoogleMapsSourceAndUtcCapturedAt_AZ484_AC5` |
+| AC-6 | Existing 200 unit + 5 smoke pass unchanged | Verified via the full suite run (handed off to autodev Step 11) |
+| AC-7 | Architecture / glossary / module-layout / contract updated | Documents amended in this batch; contract Status flipped from `draft` to `frozen` |
+
+**Contract verification** against `_docs/02_document/contracts/data-access/tile-storage.md` v1.0.0:
+- Shape: `source VARCHAR(32) NOT NULL`, `captured_at TIMESTAMP NOT NULL` — matches migration 013.
+- 5-column unique index `idx_tiles_unique_location_source` — created by migration 013.
+- Producer write API: `InsertAsync` UPSERT on the 5-column key, refreshes `captured_at`/`updated_at`/`file_path`/`tile_x`/`tile_y` — matches.
+- Consumer read API: `GetByTileCoordinatesAsync` LIMIT 1 ordered by `(captured_at DESC, updated_at DESC, id DESC)`; `GetTilesByRegionAsync` uses `DISTINCT ON (latitude, longitude, tile_zoom, tile_size_meters)` with the same tie-break tuple — matches.
+- Wire format: `TileSource.GoogleMaps → 'google_maps'`, `TileSource.Uav → 'uav'` enforced by `TileSourceTypeHandler` (necessary because the generic `EnumStringTypeHandler<T>` would emit `'googlemaps'`).
+- Inv-1 / Inv-2 / Inv-5: `NOT NULL` columns + handler `Parse` throws `DataException` on unknown values (no silent coercion per `coderule.mdc`).
+- Inv-3: 5-column unique index.
+- Inv-4: identical tie-break tuple in `GetByTileCoordinatesAsync` and the inner `DISTINCT ON` of `GetTilesByRegionAsync` guarantees identical winner per cell.
+
+### Phase 3 — Code Quality
+- SRP: `TileSourceTypeHandler` is a focused persistence concern (the bidirectional wire-format mapping); kept separate from the generic `EnumStringTypeHandler<T>` instead of leaking snake_case logic into the generic.
+- Comments: only added where intent is non-obvious (snake_case wire-format requirement, new ORDER BY tuple, per-source UPSERT semantics, transactional migration rationale). No narration-of-code comments.
+- Tests: every new test uses Arrange / Act / Assert.
+- DRY: `CreateTempTilesTable` factored out across the three TEMP-table integration tests.
+
+### Phase 4 — Security Quick-Scan
+- All SQL parameters bound (`@Source`, `@CapturedAt`, etc.) — no string interpolation of caller-supplied values.
+- Migration backfill literal is `'google_maps'`, not user input.
+- No new secrets or credentials introduced.
+
+### Phase 5 — Performance Scan
+- The new `DISTINCT ON` in `GetTilesByRegionAsync` can use `idx_tiles_unique_location_source` for the partition prefix; no extra round-trip; slow-query log threshold preserved.
+- No N+1 patterns introduced.
+
+### Phase 6 — Cross-Task Consistency
+Single-task batch. Internal consistency: enum members, wire values, migration backfill literal, and test assertions all agree on `'google_maps'` / `'uav'`.
+
+### Phase 7 — Architecture Compliance
+- Layering: `TileSource` enum lives in `SatelliteProvider.Common.Enums` (Layer 1 Foundation). DataAccess (Layer 1) and TileDownloader (Layer 3) both consume it through Common — no new cross-sibling ProjectReferences.
+- Public API respect: `TileSource` and `TileSourceTypeHandler` are public; `module-layout.md` Common Public API list updated to include `TileSource.cs`.
+- No new cycles.
+- No duplicate symbols across components.
+
+### Baseline Delta
+Not computed inline — this batch makes no structural changes that would shift the existing `_docs/02_document/architecture_compliance_baseline.md` deltas. The AZ-484 changes stay within the existing layering invariants confirmed in earlier baseline scans.
+
+## Verdict Logic
+No Critical, High, Medium, or Low findings → **PASS**.