[M1-S5] Camera follows with parallax layers #32

User story

As a player, I want the camera to lead where I'm going and the layers to drift at their own speeds, so that the small hero reads in a big, deep world.

Acceptance criteria

• Look-ahead in the move direction; smooth vertical follow
• Each layer scrolls at its docs/04 factor (0.1 sky → 1.2 foreground)
• Clamps to the chunk grid bounds; no sub-pixel shimmer

Design and references

Layer table: 04 – Layers.

Dependencies

Needs the chunk loader. Owner: Vatsal – lane B, game code (docs/13).

Verification

Walk the whole route; no seams between chunks, no shimmer at 1× and 2× scale.