Ambient Accent-Object Scatter

Same audit/backfill as Iteration 48.

• Added sparse, randomly-positioned decorative props (flowers, pebbles, logs, campfires, bones...) scattered beneath units across the battlefield -- purely decorative ground clutter, never blocking a formation from standing on a tile.
• Grew from an initial 116-prop batch to 146 after a second 30-prop batch was folded into the same pool. to 30 -- see Iteration 50 -- after the original 116-item batch turned out to be low-resolution with at least one item carrying baked-in label text.)