feat(engine): Tiled P5 — image/group layers, iso/hex/staggered coords, Wang (#73)

- Image layers: <imagelayer> renders with parallax + optional repeatx/repeaty
  tiling across the view; the image loads relative to the map file. Group layers
  flatten at build (children render in file order); layer offset/opacity/tint are
  queryable (Tiled.layer_kind / layer_offsetx / layer_offsety / layer_opacity /
  layer_tint), a group's tint applying recursively.
- Orientation transforms: Tiled.cell_x / Tiled.cell_y compute a tile cell's
  screen position for orthogonal, isometric ((x-y)*tw/2, (x+y)*th/2), staggered,
  and hexagonal (rows step by (tileh+hexsidelength)/2, alternate rows shoved per
  staggerindex) — the tile draw now places cells through them.
- Wang: exported Wang-set GIDs are ordinary GIDs and resolve through the standard
  GID resolver; the terrain-corner authoring concept is editor-side (design cut).

Proven by library/tiled_p5.ludic (14 assertions) over the real
isometric_grass_and_water.tmx (iso + Wang) and hexagonal-mini.tmx, plus a
hand-authored image+group fixture. x test: 96 passed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

changes/tiled-maps.md

@@ -9,3 +9,4 @@ type: feat
 - **P2 collision & grid (#70)** — normalise three collision sources into the byte tilemap `esys_move`/`Grid.*`/`Path.*` read, in the design's priority order: per-tile `<objectgroup>` hitboxes, the `solid`/`oneway`/`trigger` property convention (`Tiled.collision_kind`/`Tiled.tile_shapes`), and the designated collision layer (`Tiled.project`, any non-zero GID solid) — or drive collision from a visual layer's per-tile metadata alone (`Tiled.collide`). The property convention and the collision-layer fallback produce the same feed; `Path.a_star` over a loaded map matches the hand-authored baseline.
 - **P3 animated tiles + tile objects (#71)** — a tileset `<animation>` advances deterministically as a pure function of the fixed 60/s engine frame clock (`Tiled.frame_gid`/`Tiled.animated`), so an animated GID resolves at draw to the current frame's GID with its flip flags preserved and reproduces frame-for-frame across runs; `Tiled.draw_anim` draws a map with animations advanced. Object-layer entries with a `gid` render the tile image (with their own flips), bottom-anchored, as placeable sprites.
 - **P4 objects, properties, templates, spawning (#72)** — all object shapes (rectangle / ellipse / point / polygon / polyline / text) and custom properties parse and are queryable (`Tiled.object`, `Tiled.object_shape`, `Tiled.prop`/`Tiled.prop_int`/`Tiled.prop_type`); class properties resolve their defaults against a project custom-type table (`Tiled.load_types` over `objecttypes.xml`); template instances inherit their `.tx`/`.tj` template's fields; and an object maps onto Ludic components on demand (`Tiled.spawn`/`Tiled.spawn_layer`, off by default, via the reflection ABI).
+- **P5 breadth (#73)** — image layers (parallax + repeat) and group layers (flattened, with recursive offset/opacity/tint/visible; `Tiled.layer_kind`/`Tiled.layer_offsetx`/`Tiled.layer_tint`); the isometric / staggered / hexagonal orientation coordinate transforms (`Tiled.cell_x`/`Tiled.cell_y`, driving the tile draw so cells land at the correct screen coords); and Wang-set GID resolution through the standard resolver (the terrain-corner authoring concept is editor-side and ignored).