Expose documented top-level sh1pt init command

[codexwizardd]

README installation/distribution notes mention sh1pt init as the command that target plugins can pull at runtime, but the CLI currently only exposes the scaffolder as sh1pt ship init.

Expected:

• sh1pt init is available at the root and scaffolds sh1pt.config.ts using the same behavior as sh1pt ship init.
• sh1pt ship init remains available for the ship workflow.

This is a small CLI discoverability slice related to #133.