fix(ts): avoid pnpm workspace bin link warnings before build

[curtisman]

Summary

fix(ts): pnpm workspace bin link warnings

• Switch several workspace package bin entries from dist/* targets to checked-in shim entrypoints under bin/
• Add shim scripts for action-grammar, mcp-plan-validation, coder-wrapper, and kp-test
• Shims delegate to built dist/* files when present and print a clear build instruction if not yet built

docs: WSL2 setup clarification

• Add "Setup Node native module build tools" step (sudo apt install -y make build-essential) before the clone/build steps

Why

pnpm i creates executable symlinks during install. For workspace packages whose bin points directly to dist/* outputs, install warns when those compiled files don't exist yet (fresh clone before first build). The shims fix this by providing a stable, always-present entrypoint.

The WSL2 docs change makes clear that make and build-essential are required before running pnpm i / pnpm run build, preventing native module build failures.

Validation

• Ran pnpm i --ignore-scripts in ts workspace — bin-link warnings no longer reproduced for these packages