feat: add pnpm alias shims

[Stanzilla]

Summary

• add pn and pnx shims for pnpm >=11
• include the aliases in publish metadata
• mark pn init, pn dlx, and pnx as transparent pnpm commands
• add coverage for enabling alias shims and transparent alias commands

Fixes #833

Tests

• yarn build
• yarn test tests/Enable.test.ts tests/main.test.ts --run
• yarn typecheck
• yarn lint
• yarn test --run