Document default tap catalog URL

[eric-tramel]

What

Document the default NVIDIA plugin tap catalog URL as https://raw.githubusercontent.com/NVIDIA-NeMo/DataDesignerPlugins/main/catalog/plugins.json in the README and tap schema docs.

Clarify that catalog/plugins.json is generated, checked in, and consumed as raw unauthenticated JSON rather than through the GitHub API or GitHub Pages.

Document freshness semantics for mutable /main/catalog/plugins.json, immutable tag/SHA raw URLs, and possible future release assets. Also note that external taps may use any unauthenticated raw JSON endpoint or local catalog file path.

Why

Data Designer needs a stable machine-readable catalog location that works without GitHub API authentication. The docs also need to distinguish that raw catalog URL from the human-readable documentation site served from GitHub Pages.

Usage

Use the default NVIDIA tap URL for the current accepted catalog:

https://raw.githubusercontent.com/NVIDIA-NeMo/DataDesignerPlugins/main/catalog/plugins.json

Use a tag or commit SHA for an immutable snapshot:

https://raw.githubusercontent.com/NVIDIA-NeMo/DataDesignerPlugins/<tag-or-sha>/catalog/plugins.json

External taps can provide a schema v2 catalog from any unauthenticated raw JSON URL, or from a local file path for authoring and offline workflows.

How

Updated README.md, docs/tap-catalog-schema-v2.md, docs/workflow.md, and docs/index.md only. No catalog generation behavior changed; the existing generated catalog/plugins.json, make check-catalog target, and schema v2 tests remain the validation path.

Validation

• make sync
• make docs
• make check-catalog
• uv run pytest devtools/ddp/tests/test_catalog.py devtools/ddp/tests/test_tap_config.py -v (27 passed)
• git diff --check
• make check