feat: dev-assets-import — import external skills/agents into local catalog

[LucasSantana-Dev]

Summary

Implement a dev-assets-import command that lets users import skill, agent, and hook definitions from external sources (GitHub repos, npm packages, URLs) into their local catalog.

Motivation

The current workflow for adding community-maintained entries requires manually copying files and adapting them to the catalog schema. A first-class import command would lower the barrier significantly.

Proposed UX

# Import a specific skill from a GitHub repo
forge-kit import github:org/repo/skills/my-skill

# Import all entries from an npm package
forge-kit import npm:@myorg/forgekit-skills

# Import from a URL (raw GitHub, gist, etc.)
forge-kit import https://example.com/catalog/skill.json

Behavior

1. Fetch the remote definition
2. Validate it against the catalog schema (pnpm catalog:validate logic)
3. Detect ID conflicts with existing local entries and prompt for resolution
4. Write to the appropriate packages/catalog/catalog/<kind>/ directory
5. Optionally add to a collection of the user's choosing

References

• Proposed in docs/roadmap.md as dev-assets-import
• Related: plugin system design (#TBD)
• Catalog schema lives in packages/catalog/