Clean up production audit dependencies

[jurei733]

Summary

• update Angular runtime/build tooling to patched 20.3.x versions
• add production audit coverage and patch overrides for transitive build-time advisories
• move ngx-build-plus to devDependencies and remove it from the published library peerDependencies
• add explicit dev-only peer packages needed for reproducible local build and lint tooling

Validation

• npm run audit:prod -> found 0 vulnerabilities
• npm run build_cc
• npm run build:elements
• npm run test:cc -> 256 SUCCESS

Related: #146