refactor: converge build and release technical debt

[Grivn]

Summary

• make the client bundle reproducible across repeated builds and repository locations
• build JavaScript directly from src, emit declarations only, and stop tracking lib
• shrink and validate the npm tarball with explicit dependency and package-resolution checks
• establish src/shared/contracts.ts as the Host/Client wire-contract boundary
• extend Windows CI and publish the exact packed tarball
• update bilingual maintenance documentation

Validation

• pnpm run verify
• 196 tests passed (1 Windows-only smoke test skipped locally)
• all 46 generated files matched across consecutive builds
• publint strict and Are The Types Wrong ESM profile passed
• npm publish dry-run passed for the packed tarball

No product behavior, version, or release is changed by this PR.