fix(cli): reuse Pi Code managed fd/rg binaries across launches

TogetherLink points PI_CODING_AGENT_DIR at a fresh temp dir per launch,
which hid the fd/rg binaries Pi manages under ~/.pi/agent/bin, causing
an 'fd not found. Downloading...' on every Pi launch. Seed the temp
agent dir from the user's managed bin dir before launch and persist
first-time downloads back afterwards.

Also route the root pnpm test script through Turbo with an explicit
test task declaring live-test and Vitest env vars.

Bump version to 0.7.13 and rebuild release bundle.