feat(engine): Tiled P1 — rt_tmap model + GID resolver + render + projection (#69)

The heart of Tiled support: load a map and draw it.

- rt_tmap model (Tmap/TmLayer/TmTileset in tiled.ludic): map header + ordered
  layers (dense int32 GID arrays, heap-allocated to w*h, lifting the 96x64 cap)
  + tilesets. Built from the intermediate Value tree, so the TMX and TMJ paths
  both feed it.
- GID resolver (Tiled.resolve): gid -> (tileset, localId, flipH/V/D); the three
  flip flags masked off before the local-id lookup, returned alongside. gid==0
  is empty.
- Image-backed render (Tiled.draw): every visible tile layer in file order,
  blitting each tile from its tileset image with flips applied at draw.
- Compatibility projection (Tiled.project / auto on load): a designated
  collision layer projects to the legacy byte tilemap ('#' solid, '=' one-way
  via the oneway property, ' ' empty) so Grid.*/Path.*/esys_move are unchanged.
- Tiled.load resolves external tilesets + images relative to the map file and
  auto-projects a collision/solids/walls layer.
- The grid and physics_tiles demos now run off a loaded map (grid_maze.tmx /
  physics_map.tmx) instead of hand-authored Map.row strings, byte-identically.

Two compiler fixes fell out of this (see the changeset):
- emit_index_addr set g_addr_ty before evaluating the index, so slice[obj.field]
  came back mis-typed; set it last, like the raw-pointer branches.
- @strcmp was declared by both the world table and the fs prelude; centralise
  it in the head prelude so a game that uses Fs/Path links.

Proven by library/tiled_p1.ludic (14 assertions: loads+renders Kenney map
identically from .tmx and .tmj, flip mirroring) + the converted grid/
physics_tiles demos. x test: 92 passed; self-host bootstrap fixpoint intact.

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

tools/docgen/inventory.json

@@ -684,6 +684,17 @@
   ],
   "tiled": [
     "tiled-read",
-    "tiled-read_tsx"
+    "tiled-read_tsx",
+    "tiled-load",
+    "tiled-gid",
+    "tiled-resolve",
+    "tiled-width",
+    "tiled-height",
+    "tiled-layer_count",
+    "tiled-layer_name",
+    "tiled-draw",
+    "tiled-project",
+    "tiled-tree",
+    "tiled-tile_prop"
   ]
 }

tools/x/test.ludic

@@ -207,6 +207,7 @@ function cmd_test() -> int {
   feat_case("library/serialize", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16", "serialize.ludic (Value tree + Json encode/parse + Reflect.serialize/apply — bit-exact save/load; issue #44)")
   feat_case("library/tiled_p0", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21", "tiled_p0.ludic (Tiled P0: Xml reader + Base64 decode/encode + gzip framing over inflate; issue #67)")
   feat_case("library/tiled_p05", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30", "tiled_p05.ludic (Tiled P0.5: TMX/TSX reader -> same Value-tree intermediate as TMJ; Kenney sampleMap.tmx; issue #68)")
+  feat_case("library/tiled_p1", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14", "tiled_p1.ludic (Tiled P1: rt_tmap model + GID resolver/flip decode + render; loads+draws Kenney map identically from .tmx and .tmj; issue #69)")
   feat_case("library/render", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18", "render.ludic (Screen pixel/oval/camera/clip/blend_mode/measure_text + Camera set/follow/shake, verified by pixel readback)")
   feat_case("library/lighting", "", "1 2 3 4 5 6 7 8 9 10 11 12 13 14", "lighting.ludic (Light ambient/point radial falloff + occluder hard shadows — 2D light accumulation, verified by pixel readback)")
   feat_case("library/light_tiers", "", "1 1 1 1 1 1 1 1 1", "light_tiers.ludic (Light spot/falloff/soft/gel/normal/time_of_day — render-quality tiers 3-4; issue #49)")