fix: add pi-agent-sdk to AGENT_PROVIDER_KINDS

[christso]

Problem

AGENT_PROVIDER_KINDS in packages/core/src/evaluation/providers/types.ts lists agent providers with filesystem access, but pi-agent-sdk is missing. It appears to be an agent with filesystem access similar to pi-coding-agent.

This means pi-agent-sdk targets are treated as non-agent providers for guideline handling and any logic that relies on AGENT_PROVIDER_KINDS or isAgentProvider().

Fix

Add 'pi-agent-sdk' to the AGENT_PROVIDER_KINDS array if it does indeed have filesystem access.

Architecture boundary

core-runtime