Remove package verification framework

[roackb2]

What changed

• remove the custom manifest, package-family, npm-pack, and fresh-consumer verifier scripts
• remove tests whose only subject was that verification framework
• stop running package verifiers from compilation, typecheck, build, and PR CI
• keep ordinary package builds, product tests, PostgreSQL tests, Execution Host conformance, and contract artifact checks
• simplify the manual release guide to build, test, and publish directly

Why

The verifier layer duplicated package manifests and release policy in more than two thousand lines of custom code. At this stage, failed publication can be corrected directly; maintaining a parallel framework is a larger cost than the release risk it addresses.

Validation

• yarn typecheck
• yarn lint
• yarn test:unit — 135 files, 859 tests
• yarn build