Replace "seam" with clearer terms throughout:
- "surface" for public API/extension boundaries
- "boundary" for plugin/module interfaces
- "interface" for runtime connection points
- "hook" for test injection points
- "palette" for the lobster palette reference
Also delete experiments/acp-pluginification-architecture-plan.md
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
