Register catalog packages on first release

[eric-tramel]

What

Changes the catalog maintenance model from broad full-repo sync as the normal path to targeted first-release registration.

• Adds ddp catalog register <plugin> to add one package to catalog/plugins.json.
• Keeps ddp new scaffold-only, so experimental or unreleased packages are not catalog-visible by default.
• Changes make catalog to require PLUGIN=<package> and call targeted registration.
• Changes make check-catalog to validate the checked-in catalog JSON instead of requiring every local package to be synced.
• Keeps full ddp sync catalog available as an explicit escape hatch.
• Updates release validation, tests, docs, and the PR checklist for the first-release registration model.

Why

Package publication is now release-driven, so catalog discoverability should also become release-intentional. A new scaffolded package should not automatically appear in the public catalog; it should be registered only when maintainers are preparing its first installable release.

Usage

For a new package, scaffold and develop normally without touching the catalog:

uv run ddp new my-plugin

When preparing the package's first release, register it once:

make catalog PLUGIN=data-designer-my-plugin

For later version releases, reuse the existing registration. If registration metadata must be corrected intentionally:

uv run ddp catalog register data-designer-my-plugin --replace

Workflow

flowchart TD
    A[Scaffold package<br/>uv run ddp new my-plugin] --> B[Develop plugin code, docs, tests]
    B --> C{Ready for first release?}
    C -- No --> B
    C -- Yes --> D[Register catalog package<br/>make catalog PLUGIN=data-designer-my-plugin]
    D --> E[Review and commit catalog/plugins.json]
    E --> F[Merge registration to main]
    F --> G[Run release process<br/>make release PLUGIN=data-designer-my-plugin PUBLISH=1]
    G --> H[Publish workflow uploads package assets<br/>and updates packages.json]
    H --> I[Docs workflow deploys Pages<br/>catalog + simple index]
    I --> J[Users discover package from catalog<br/>and install from static index]

    K[Subsequent version release] --> G

Loading

How

register_catalog_package() builds catalog entries for a single package directory, loads entry points from source so registration does not require a prior editable install, and merges just that package into the existing catalog. Existing registrations are protected unless --replace is passed.

ddp catalog check reads and validates the checked-in catalog contract. The old full regeneration path remains available through ddp sync catalog, but it is no longer the Makefile's normal catalog check or update path.

Validation

• make lint
• make test-devtools
• make check
• make docs

[johnnygreco]

Reviewed the catalog registration flow, source-loading path, CLI/Makefile wiring, release validation updates, and docs. Local validation is green (make lint, make test-devtools, make check, make docs), and the PR checks are passing. Looks good to me.