Preserve availability after failed npm self-updates

[LeanAndMean]

Summary

• route package and config commands through a shared early dispatcher so self-update can run without loading the full Scramjet runtime
• qualify supported npm/POSIX installations and perform package-tree updates with bounded structural and launcher verification
• restore the previous launcher and package runtime after returned update failures while retaining and reporting cleanup artifacts without disturbing a verified installation
• add phase-specific diagnostics, destructive transaction coverage, packed product-only and pre-populated CI proofs, and synchronized recovery documentation

Test plan

• Run focused early-dispatch, qualification, transaction, package-manager CLI, and launcher-bootstrap tests
• Run type checking, the full topological build, and lint
• Run the full test suite; verify the two load-sensitive timeout cases pass in isolation
• Exercise packed product-only and pre-populated installation layouts
• Verify destructive failed-update restoration on real NFS with the installed native addon held open

Fixes #459