[AZ-794] [AZ-795] [AZ-796] Strict input validation + z/x/y rename

AZ-794: rename inventory wire fields tileZoom/tileX/tileY -> z/x/y
to match the slippy-map URL convention. Contract bumped to v2.0.0.

AZ-795: shared validation infrastructure -- FluentValidation +
ValidationEndpointFilter + GlobalValidatorConfig (camelCase paths).
GlobalExceptionHandler now converts JsonException (UnmappedMember +
JsonRequired) into RFC 7807 ValidationProblemDetails. JSON layer
hardened with UnmappedMemberHandling.Disallow + camelCase naming
policy. New error-shape.md contract.

AZ-796: InventoryRequestValidator covers 9 rules (XOR tiles vs
locationHashes, cap 1000, z 0..22, x/y in slippy bounds, hash
length/charset). 16 unit tests + 16 integration tests + a manual
curl probe script.

Adjacent fixes uncovered by the new strict layer:
- IdempotentPostTests RoutePoint payload corrected to lat/lon
  (the DTO has used JsonPropertyName for ages; previously silently
  ignored under PascalCase fallback).
- TileInventoryTests slippy x/y reduced to fit z=18 bounds.
- docker-compose.yml host port for Postgres moved 5432 -> 5433 to
  avoid sibling-project conflict; appsettings.Development + README
  + AGENTS + architecture + containerization docs aligned.

New coderule (suite + repo): API consumer-facing OpenAPI
descriptions must not contain task IDs, contract filenames, or
version-bump history -- internal change tracking belongs in
commits/contract docs/changelogs. Existing offending descriptions
in Program.cs cleaned up.

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

SatelliteProvider.Services.TileDownloader/TileService.cs

@@ -173,8 +173,8 @@ public class TileService : ITileService
         {
             foreach (var coord in tiles!)
             {
-                var hash = Uuidv5.LocationHashForTile(coord.TileZoom, coord.TileX, coord.TileY);
-                entries.Add((coord.TileZoom, coord.TileX, coord.TileY, hash));
+                var hash = Uuidv5.LocationHashForTile(coord.Z, coord.X, coord.Y);
+                entries.Add((coord.Z, coord.X, coord.Y, hash));
             }
         }
         else
@@ -195,9 +195,9 @@ public class TileService : ITileService
             {
                 results.Add(new TileInventoryEntry
                 {
-                    TileZoom = hasTiles ? zoom : tile.TileZoom,
-                    TileX = hasTiles ? x : tile.TileX,
-                    TileY = hasTiles ? y : tile.TileY,
+                    Z = hasTiles ? zoom : tile.TileZoom,
+                    X = hasTiles ? x : tile.TileX,
+                    Y = hasTiles ? y : tile.TileY,
                     LocationHash = hash,
                     Present = true,
                     Id = tile.Id,
@@ -211,9 +211,9 @@ public class TileService : ITileService
             {
                 results.Add(new TileInventoryEntry
                 {
-                    TileZoom = zoom,
-                    TileX = x,
-                    TileY = y,
+                    Z = zoom,
+                    X = x,
+                    Y = y,
                     LocationHash = hash,
                     Present = false
                 });