Every pin move re-rendered the Puppet's input (source, masks and the
effects before it) at full size on the UI thread and deep-copied it
for the mesh overlay: the cache key of a layer's input hashed all of
its effects, so moving a pin of the Puppet changed the key of its own
input. The input key now covers only the effects that run before the
Puppet, and the overlay shares the cached buffer.
Test: input_keys_ignore_later_effects.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018gnTnH3Jmk5zr4tMq1Mc9f