Complete the overworld foundation

Port forced movement (turn delays, bumps, ice, currents, pits), dynamic
return warps, elevators, Surf, Cut, Strength and cycling rules, working
map blocks with changeblock/changemapblocks, and the remaining NPC
movement types and movement commands.

Add tileset animation from the ROM's command tables, grass sprite
priority and special map palettes; room decorations with ownership, the
bedroom PC and save migration; and Key Items access to the Bicycle.

Fourteen original-engine traces compare positions, facing, actors, event
flags and scripted poses. Tile animation matches original VRAM for four
tilesets, and LoadMapPals matches 192 palette cases. skyfall_top now
keeps the $60 sprite offset its step function leaves behind.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/rendering.test.ts

@@ -0,0 +1,87 @@
+import { describe, expect, it } from "vitest";
+import { existsSync, readFileSync } from "node:fs";
+import { drawTile } from "../src/game/rendering/pixels";
+import { TilesetAnimator } from "../src/game/rendering/tileset-animation";
+import { CrystalAssets } from "../src/game/rom/assets";
+import { OW } from "../src/game/world/constants";
+import type { Palette } from "../src/game/world/types";
+
+it("grass priority uses background indices, preserving transparent sprite pixels", () => {
+  const palette: Palette = [
+    [255, 255, 255],
+    [80, 160, 80],
+    [32, 64, 32],
+    [0, 0, 0],
+  ];
+  const target = new Uint8ClampedArray(8 * 8 * 4);
+  const indices = new Uint8Array(8 * 8);
+  const background = new Uint8Array(16);
+  background[0] = 0x80; // Colored grass at x=0; color zero elsewhere.
+  drawTile(target, 8, 8, background, 0, 0, 0, palette, { indices });
+  const sprite = new Uint8Array(16);
+  sprite[1] = 0xc0; // Sprite color 2 at x=0 and x=1, transparent at x=2.
+  drawTile(target, 8, 8, sprite, 0, 0, 0, palette, {
+    indices,
+    behind: true,
+    transparent: true,
+  });
+  expect([...target.slice(0, 12)]).toEqual([
+    80, 160, 80, 255, 32, 64, 32, 255, 255, 255, 255, 255,
+  ]);
+  expect([...indices.slice(0, 3)]).toEqual([1, 0, 0]);
+  drawTile(target, 8, 8, sprite, 0, 0, 0, palette, {
+    indices,
+    transparent: true,
+  });
+  expect([...target.slice(0, 4)]).toEqual([32, 64, 32, 255]);
+});
+
+const romPath =
+  process.env.CRYSTAL_ROM_PATH ??
+  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
+describe.skipIf(!existsSync(romPath))(
+  "overworld rendering with the local ROM",
+  () => {
+    it("runs every tileset animation without changing the cached ROM graphics", () => {
+      const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
+      const base = assets.map("24:4");
+      for (let tileset = 1; tileset <= OW.NUM_TILESETS; tileset++) {
+        const map = { ...base, tileset };
+        const graphics = assets.tileset(map).graphics;
+        const original = graphics.slice();
+        const animator = new TilesetAnimator(assets, map, graphics);
+        animator.advance(1024, false);
+        animator.advance(1024, true);
+        expect(graphics, `tileset ${tileset}`).toEqual(original);
+        expect(animator.graphics.length).toBe(original.length);
+      }
+    });
+
+    it("keeps special indoor palettes fixed and uses normal palettes for the Hall of Fame", () => {
+      const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
+      const base = assets.map("24:6");
+      for (const tileset of [
+        OW.TILESET_POKECOM_CENTER,
+        OW.TILESET_BATTLE_TOWER_INSIDE,
+        OW.TILESET_HOUSE,
+        OW.TILESET_RADIO_TOWER,
+        OW.TILESET_MANSION,
+      ]) {
+        const map = { ...base, tileset };
+        expect(assets.palettes(map, 0)).toEqual(assets.palettes(map, 2));
+        expect(assets.palettes(map, 0)).toHaveLength(8);
+      }
+      const ice = {
+        ...base,
+        tileset: OW.TILESET_ICE_PATH,
+        environment: OW.CAVE,
+      };
+      expect(assets.palettes(ice, 0)).toEqual(assets.palettes(ice, 2));
+      const hall = { ...ice, environment: OW.INDOOR };
+      expect(assets.palettes(hall, 1)).not.toEqual(assets.palettes(ice, 1));
+      expect(assets.palettes(hall, 1)).toEqual(
+        assets.palettes({ ...hall, tileset: OW.TILESET_POKECENTER }, 1),
+      );
+    });
+  },
+);