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>

README.md

@@ -6,9 +6,9 @@ A native web port of Pokémon Crystal, translated from [PRET's Game Boy disassem
 
 Walk around your home, the town and its buildings at the original walking speed. Mom gives you the Pokégear and asks the day of the week. The teacher stops you from leaving town. Your rival shoves you away from the lab window. Professor Elm introduces his errand, and you choose Chikorita, Cyndaquil or Totodile. The Pokémon's picture and stats come from your ROM, and you can nickname it. Elm's aide then gives you a Potion. These scenes run the game's own event scripts and movement data, with native choices and naming.
 
-With a Pokémon, head west along Route 29 to Cherrygrove City. Wild Pokémon appear in the grass and battle you with their original moves. The route has ledges, signs, an item ball and a Berry tree that regrows daily. In Cherrygrove, the Guide Gent gives a tour, the Poké Mart buys and sells items, the Pokémon Center nurse heals your party, and a whiteout returns you to the last Pokémon Center you entered.
+With a Pokémon, head west along Route 29 to Cherrygrove City. Wild Pokémon appear in the grass and battle you with their original moves. The route has ledges, signs, an item ball and a Berry tree that regrows daily. Townspeople wander and look around as in the original. In Cherrygrove, the Guide Gent gives a tour, the Poké Mart buys and sells items, the Pokémon Center nurse heals your party, and a whiteout returns you to the last Pokémon Center you entered.
 
-Catching, trainer battles, Route 30 and beyond, party and bag menus, random NPC movement, decorations and audio are still being ported. Unported neighboring areas appear at the edges but cannot be entered yet.
+Catching, trainer battles, Route 30 and beyond, party and bag menus, decorations and audio are still being ported. Unported neighboring areas appear at the edges but cannot be entered yet.
 
 ## Run