chore(release): document publish blockers

Evaluated readiness to publish @headless-coder-sdk/core plus the three adapters to npm/pnpm. They currently depend on each other via file:../ paths (see packages/*/package.json), which npm rejects for published packages. Release will require replacing those local references with proper semver ranges (e.g., ^0.1.0) and ensuring the dist artifacts are built before running npm publish.

Author: OhadAssulin