[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.Common/DTO/TileInventory.cs

@@ -1,3 +1,5 @@
+using System.Text.Json.Serialization;
+
 namespace SatelliteProvider.Common.DTO;
 
 // AZ-505: bulk-list / inventory request envelope. Either `Tiles` OR
@@ -12,21 +14,33 @@ public sealed class TileInventoryRequest
     public IReadOnlyList<Guid>? LocationHashes { get; set; }
 }
 
-// AZ-505: Slippy-map tile coordinate triple. Field naming matches the on-wire
-// snake_case used by the existing `GET /tiles/{z}/{x}/{y}` and the AZ-484/AZ-503
-// `tiles` table columns (`tile_zoom`, `tile_x`, `tile_y`).
+// AZ-505: Slippy-map tile coordinate triple. AZ-794 (cycle 7) renamed the
+// wire-format fields from `tileZoom/tileX/tileY` → `z/x/y` to align with the
+// OSM / slippy-map convention already used by `GET /tiles/{z}/{x}/{y}` and
+// to shave wire-size on inventory requests carrying thousands of entries.
+// The C# property names (`Z`, `X`, `Y`) intentionally mirror the wire names
+// 1:1 so consumers don't need to mentally translate at the deserialization
+// boundary. The DataAccess `TileEntity.TileZoom/TileX/TileY` columns are
+// unchanged — that's a database identity, not a wire format.
 public sealed class TileCoord
 {
-    public int TileZoom { get; set; }
-    public int TileX { get; set; }
-    public int TileY { get; set; }
+    [JsonRequired]
+    public int Z { get; set; }
+
+    [JsonRequired]
+    public int X { get; set; }
+
+    [JsonRequired]
+    public int Y { get; set; }
 }
 
 // AZ-505: Inventory response. Entries are returned in the SAME ORDER as the
 // matching request input (per AC-1). When Request.Tiles was populated, each
-// entry's `TileZoom`/`TileX`/`TileY` echoes the request entry; when
-// Request.LocationHashes was populated, the coord triple fields are 0 (the
-// caller already knows the hash and can map it back themselves).
+// entry's `Z`/`X`/`Y` echoes the request entry; when Request.LocationHashes
+// was populated, the coord triple fields are 0 (the caller already knows
+// the hash and can map it back themselves). AZ-794 (cycle 7) renamed the
+// coord triple to `z/x/y` to align wire format with the URL-path
+// convention.
 public sealed class TileInventoryResponse
 {
     public IReadOnlyList<TileInventoryEntry> Results { get; set; } = Array.Empty<TileInventoryEntry>();
@@ -40,11 +54,14 @@ public sealed class TileInventoryResponse
 // `EstimatedBytes` is intentionally absent in v1.0.0 — adding the per-row
 // `stat()` cost is deferred until production profiling justifies it (see
 // AZ-505 Outcome bullet 1 + Excluded list).
+//
+// AZ-794 (cycle 7): coord triple renamed `tileZoom/tileX/tileY` → `z/x/y`
+// (contract bumped to v2.0.0).
 public sealed class TileInventoryEntry
 {
-    public int TileZoom { get; set; }
-    public int TileX { get; set; }
-    public int TileY { get; set; }
+    public int Z { get; set; }
+    public int X { get; set; }
+    public int Y { get; set; }
     public Guid LocationHash { get; set; }
     public bool Present { get; set; }