feat: scream when hedgehog is harshly thrown

[fercgomes]

Summary

When hedgehog mode is enabled and the user grabs the hog and flings it sharply upward, play the Wilhelm scream.

• Detection is purely renderer-side via the @posthog/hedgehog-mode package's public API: on every pointerup we defer one animation frame so Matter.js has applied the post-release velocity, then inspect each hedgehog's rigidBody.velocity. If a hog is moving upward faster than the autonomous jump speed (y < -25 AND speed > 25), we play the scream at the user's completionVolume.
• The wilhelm.mp3 asset already shipped as a selectable task-completion sound; this just wires it to throw releases as well via a new one-shot playSoundUrl helper that doesn't interfere with the completion-sound audio chain.

Thresholds are an initial guess (25 in Matter.js units, comfortably above the autonomous jump() velocity of 15). Easy to tune.

Test plan

• pnpm --filter code typecheck (already green locally)
• Enable hedgehog mode in settings
• Grab the hog and fling it sharply upward → Wilhelm scream plays
• Grab the hog and drop/shake it sideways at moderate speed → no scream
• Let the hog jump autonomously → no scream
• Trigger a task-completion sound, then immediately throw the hog → both audio clips play (do not cancel each other)
• Set completionVolume = 0 → throws are silent
• Disable hedgehog mode → no scream on subsequent pointerups