Document plugin tap governance and trust

[eric-tramel]

What

Documents DDPlugins as the NVIDIA-maintained curated first-party tap for Data Designer and adds trust guidance for default and non-default tap install flows.

The update covers:

• first-party contribution fit for plugins in DDPlugins
• when external/team/community plugins should publish external taps instead
• raw schema v2 JSON requirements for external taps
• tap installation trust language for future Data Designer CLI implementation
• concrete confirmation fields for installs from non-default taps

Why

Issue #24 needs the docs to make tap governance explicit before the CLI follow-up work references this repository as the canonical trust model. A tap is not just a search preference; it points users at Python packages that will be resolved, installed, and imported.

Usage

First-party plugins should land in DDPlugins only when they are NVIDIA-maintained, broadly useful to Data Designer users, and have an accountable CODEOWNER.

External plugins can publish a schema v2 tap instead of landing here. The tap should be exposed as an unauthenticated raw JSON catalog URL, for example:

https://example.com/data-designer/plugins.json

Future CLI install flows can reference the documented confirmation shape for non-default taps:

Tap: https://example.com/data-designer/plugins.json
Package: data-designer-example==0.1.0
Source: git https://github.com/example/data-designer-example.git @ v0.1.0
Command: uv pip install "data-designer-example @ git+https://github.com/example/data-designer-example.git@v0.1.0"

How

Added scoped prose to hand-authored docs only:

• README.md for repository-level governance and trust language
• docs/authoring.md for first-party contribution criteria and external tap guidance
• docs/index.md for the docs landing page repository contract
• docs/tap-catalog-schema-v2.md for schema v2 raw JSON requirements and CLI confirmation semantics

Generated plugin docs were not edited manually.

Validation

• make sync
• git diff --check
• make docs
• make check