packages CLI: scaffold a new Package #301

This was generated by AI during triage.

Agent Brief

Category: enhancement
Summary: Add an offline packages new command backed by a maintained reference Package.

Current behavior:
A public checkout has no reliable scaffold command or guaranteed local reference Package.

Desired behavior:
lyracore packages new <name> validates the name, refuses enabled and disabled-name collisions, and creates a minimal Package from a versioned reference template available to a public checkout. The result can be Rust-only, client-only, or expanded with Datascripts and Runtime Scripts without changing its identity.

Key interfaces:

• lyracore packages new <name>
• Versioned reference Package template

Acceptance criteria:

• The command works without network access in a fresh public checkout.
• The scaffold passes preflight without manual registration edits.
• The generated Package name is valid as a folder and generated Rust identifier.
• Existing enabled or disabled Packages are never overwritten.
• Output explains how to build, publish, and synchronize relevant Package content.

Out of scope:

• Installing the scaffold into the Official Package Collection
• Interactive feature selection