[RohanFredriksson]

Batch 4 of ROADMAP.md.

• CameraFollow component: follows its own entity, or another by id, with an offset, exponential smoothing that doesn't depend on frame rate, a dead zone, and bounds that keep the view inside them (or centre it when it doesn't fit). It snaps on start and when the target changes, and is serialised. The logic is in apply(camera, target, dt), so it is tested without a window.
• Camera::shake(intensity, duration) moves the view by a random offset that fades out quadratically, keeping the stronger of overlapping shakes. Only getView changes, so the camera's position, following and mouse world coordinates are unaffected. A paused scene holds the offset.
• GamepadListener: polled each frame after glfwPollEvents. Buttons have down, begin down and end down (compared with the previous poll, and a disconnect releases everything). Axes have a configurable dead zone, applied radially to sticks. Stick y points up, and triggers go from 0 to 1. setState lets tests and tools fake a pad.
• Console commands shake and gamepads.
• The demo shakes the camera on hard impacts, and a gamepad's left stick pans and A drops a box.

Tests: new unit test test_camera for shake, follow (snap, frame-rate independent smoothing, dead zone, offset, bounds, json) and gamepad state, and engine test test_camera_engine for following through the scene, changing and losing the target, shake from the console, and per-frame polling.

Claude-Session: https://claude.ai/code/session_015cNAkNqoDWA5gFReD1AsqV