Fix Windows CI build (currently a no-op placeholder)

The Windows build job in `.github/workflows/build.yml` has `continue-on-error: true` on every meaningful step. It always passes regardless of actual build success.

**Required:**
- Remove `continue-on-error: true` from build steps
- Ensure Windows build actually compiles and produces working artifacts
- Fix any underlying build issues on the Windows target

Start with .github/workflows/build.yml and inspect every Windows build step that uses continue-on-error. Run the Windows job after removing those allowances, then investigate the failures it exposes. Done means the Windows target compiles successfully and produces working artifacts without masked errors.

Written by the indexing model from the issue text.