[AZ-503] Tile identity → UUIDv5 + integer UPSERT (foundation)

Foundation half of original AZ-503 (split during /autodev step 10 batch 2
on user choice; deferred work moved to AZ-505 with a Blocks link).

Adds deterministic tile identity (UUIDv5 over (z, x, y, source, flight_id))
shared cross-repo with gps-denied-onboard via the pinned TileNamespace
5b8d0c2e-7f1a-4d3b-9c5e-1f3a8e7d2b6c, switches the tiles UPSERT key from
floats to integers with per-flight separation, plumbs FlightId through
UavTileMetadata + handler, and writes UAV evidence to per-flight
on-disk directories so two flights at the same (z, x, y) coexist.

- Common: pure-C# RFC 9562 Uuidv5 (no third-party dep) + FlightId DTO
  field; 10 Python-reference unit vectors verify byte parity.
- DataAccess: migration 014 adds flight_id (uuid NULL), location_hash
  (uuid NOT NULL, backfilled via session-scoped pg_temp.uuidv5),
  content_sha256 (bytea NULL), legacy_id (uuid NULL = preserves
  pre-AZ-503 random id one cycle); drops idx_tiles_unique_location_source
  (AZ-484) and adds idx_tiles_unique_identity keyed on
  (tile_zoom, tile_x, tile_y, tile_size_meters, source,
   COALESCE(flight_id, '00000000-...'::uuid)) + idx_tiles_location_hash.
- TileRepository: ColumnList + UPSERT updated; id never updated on
  conflict (preserves AC-2 idempotence). UpdateAsync extended.
- Services: TileService and UavTileUploadHandler compute deterministic
  Id + LocationHash + ContentSha256 before insert; UAV file path
  becomes ./tiles/uav/{flight_id or 'none'}/{z}/{x}/{y}.jpg.
- Tests: Uuidv5Tests (10 reference vectors), UavTileFilePathTests
  (per-flight + anonymous paths), UavTileUploadHandlerTests (AC-2,
  AC-3, AC-7, AC-11 unit-level), UavUploadTests (AC-3 + AC-4
  integration: multi-flight DB coexistence with shared location_hash
  + distinct file_path; float-different lat/lon collapse to 1 row),
  MigrationTests (column shape, idx_tiles_unique_identity supersedes
  AZ-484 index, deterministic backfill).
- IntegrationTests project references Common to reuse Uuidv5 in raw
  SQL seeds.
- AZ-488 MultiSourceCoexistence seed fixed to populate location_hash
  (otherwise migration 014's NOT NULL constraint fails).

ACs covered: AC-1, AC-2, AC-3, AC-4, AC-7, AC-8, AC-11.
ACs deferred to AZ-505: AC-5, AC-6, AC-9, AC-10, AC-12.

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

SatelliteProvider.DataAccess/Models/TileEntity.cs

@@ -24,4 +24,26 @@ public class TileEntity
     public DateTime CapturedAt { get; set; }
     public DateTime CreatedAt { get; set; }
     public DateTime UpdatedAt { get; set; }
+
+    // AZ-503: per-UAV-flight identifier. NULL for google_maps and pre-AZ-503
+    // legacy UAV rows; populated for AZ-503+ UAV uploads. Part of the UPSERT
+    // conflict key (via COALESCE to the zero-UUID) so two flights uploading
+    // the same (z, x, y) cell coexist as distinct rows.
+    public Guid? FlightId { get; set; }
+
+    // AZ-503: UUIDv5(TILE_NAMESPACE, "{tile_zoom}/{tile_x}/{tile_y}"). Always
+    // populated (column is NOT NULL after migration 014); deterministic across
+    // C# and Python (see SatelliteProvider.Common.Utils.Uuidv5).
+    public Guid LocationHash { get; set; }
+
+    // AZ-503: SHA-256 of the tile body at insert time. NULL for pre-AZ-503
+    // legacy rows (the migration cannot read tile files); NOT NULL by
+    // application invariant for AZ-503+ inserts (TileService.BuildTileEntity
+    // and UavTileUploadHandler.PersistAsync compute this before insert).
+    public byte[]? ContentSha256 { get; set; }
+
+    // AZ-503: pre-AZ-503 random Id value, preserved for one deprecation cycle
+    // so external references to the legacy random id can be reconciled (per
+    // AZ-503 Risk 1 mitigation). Dropped in a follow-up migration.
+    public Guid? LegacyId { get; set; }
 }