Let NPCs roam as HandleNPCStep does

- Random walks and spins from SpriteMovementData, with random sleeps.
- CanObjectMoveInDirection: side walls, land, objects' current and
  previous tiles, the radius (stored plus one) and the screen edge.
- Objects freeze while text is open and during applymovement, and
  return home when both they and their home leave the object window.
- Wandering positions are not saved; test helpers replan around NPCs.

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

src/game/rom/assets.ts

@@ -5,6 +5,7 @@ import {
   MAP_GROUP_COUNT,
   NATIVE_MAPS,
   NUM_ENGINE_FLAGS,
+  NUM_SPRITEMOVEDATA,
   RAM,
   SYMBOLS,
 } from "./profile";
@@ -165,6 +166,7 @@ export class CrystalAssets {
         y: r.byte(p + 1) - 4,
         x: r.byte(p + 2) - 4,
         movement: r.byte(p + 3),
+        radius: r.byte(p + 4),
         hour1: r.byte(p + 5),
         hour2: r.byte(p + 6),
         palette: r.byte(p + 7) >> 4,
@@ -374,6 +376,18 @@ export class CrystalAssets {
     }
     return flags;
   }
+  /** SpriteMovementData for a SPRITEMOVEDATA_* type: the movement
+   * function, flags1 (FIXED_FACING, NOCLIP_*, ...) and palette flags. */
+  spriteMovement(type: number): {
+    fn: number;
+    flags: number;
+    paletteFlags: number;
+  } {
+    if (type >= NUM_SPRITEMOVEDATA) throw new Error("Unknown movement type.");
+    const r = this.reader,
+      p = SYMBOLS.spriteMovementData + type * 6;
+    return { fn: r.byte(p), flags: r.byte(p + 3), paletteFlags: r.byte(p + 5) };
+  }
   /** Emote bubble graphics (data/sprites/emotes.asm). */
   emote(index: number): Uint8Array {
     const r = this.reader,

src/game/rom/profile.ts

@@ -52,6 +52,7 @@ export const SYMBOLS = {
   fruitTreeScript: 0x44000,
   fruitTreeItems: 0x44097,
   engineFlags: 0x80462,
+  spriteMovementData: 0x4273,
   marts: 0x160a9,
   martWelcomeText: 0x15f83,
   martAskMoreText: 0x15fb9,
@@ -256,6 +257,7 @@ export const NUM_POKEMON = 251;
 export const NUM_ITEMS = 190;
 export const NUM_ENGINE_FLAGS = 162;
 export const NUM_FRUIT_TREES = 30;
+export const NUM_SPRITEMOVEDATA = 37;
 /** The last group has no following pointer to bound it. */
 export const LAST_MAP_GROUP_SIZE = 11;