Fix npm provenance and prepare pre.75

[halfaipg]

Summary

• align npm repository metadata with the canonical codebase/codebase-cli repository
• canonicalize shipped GitHub links and reject retired repository references in help smoke
• fail releases before packaging when repository.url cannot match GitHub provenance
• prepare 2.0.0-pre.75 after npm rejected pre.74 provenance

Verification

• npm run check (1,288 tests)
• npm run build
• npm run smoke:help
• npm pack --dry-run confirms 559 files and canonical repository metadata