🐛 fix terrain canvas not updating after tile changes (Issue #22)

CHANGE_TILE only called worldSystem.setTile() (built-tile layer only),
never refreshTerrainTile() — so chopped trees stayed visually dark-green
(FOREST color) even though the tile type was already DARK_GRASS.

- adapter.onAction for CHANGE_TILE now also calls refreshTerrainTile()
  → all tile transitions (chop, mine, seedling maturation) update the
    canvas pixel immediately and consistently in one place
- Remove now-redundant explicit refreshTerrainTile() call in
  TreeSeedlingSystem (the adapter handler covers it)
- Tile-recovery path in GameScene (stateManager.tickTileRecovery) is
  NOT routed through the adapter, so its manual refreshTerrainTile()
  call is kept as-is

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/scenes/GameScene.ts

@@ -78,6 +78,7 @@ export class GameScene extends Phaser.Scene {
     this.adapter.onAction = (action) => {
       if (action.type === 'CHANGE_TILE') {
         this.worldSystem.setTile(action.tileX, action.tileY, action.tile)
+        this.worldSystem.refreshTerrainTile(action.tileX, action.tileY, action.tile)
       } else if (action.type === 'SPAWN_RESOURCE') {
         this.resourceSystem.spawnResourcePublic(action.resource)
         this.worldSystem.addResourceTile(action.resource.tileX, action.resource.tileY)