Make the buzz-cli skill available to Pi agents

🤖 Buzz provisions the managed `buzz-cli` skill under `~/.buzz/.agents/skills`, but Pi running through `pi-acp` does not load project-local skills from the untrusted `~/.buzz` working directory.

Teach the Pi preset to explicitly pass Buzz's managed skill directory to `pi-acp`, after the adapter supports forwarding explicit skill paths to Pi. Keep the opt-in scoped to Buzz so other `pi-acp` clients retain Pi's project-trust behavior.

Start by locating the Pi preset and the pi-acp adapter, then inspect how the adapter forwards explicit skill paths. Confirm that Buzz's managed ~/.buzz/.agents/skills directory is passed only by the Buzz Pi preset, while other pi-acp clients retain Pi's project-trust behavior; done means the buzz-cli skill is available to Pi agents.

Written by the indexing model from the issue text.