What

Adds a top-level documentation page that defines the schema v2 tap catalog contract for issue #16. The page specifies the required top-level fields, required plugin entry fields, source object union, validation rules, and examples for PyPI, Git, and path install sources.

It also links the new page from the docs index and Zensical navigation so implementers can find the contract before catalog generation and consumer work lands.

Closes #16.

Why

The tap work needs one concrete JSON contract before later workers update catalog generation, schema validation, and Data Designer CLI consumers. This page removes the schema shape as an open decision and records the important layer boundaries: tap discovery reads catalog data, runtime entry-point discovery happens only after package installation, and package.path is repo-local metadata rather than a remote install source.

Usage

Use docs/tap-catalog-schema-v2.md as the implementation reference for schema v2 catalogs. For example, a released package source is represented as:

{
  "type": "pypi",
  "package": "data-designer-example"
}

A Git subdirectory source is represented as:

{
  "type": "git",
  "url": "https://github.com/NVIDIA-NeMo/DataDesignerPlugins.git",
  "ref": "data-designer-example/v0.1.0",
  "subdirectory": "plugins/data-designer-example"
}

A local authoring source is represented as:

{
  "type": "path",
  "path": "plugins/data-designer-example",
  "editable": true
}

How

This is documentation-only. It adds docs/tap-catalog-schema-v2.md, updates docs/index.md, and adds a low-risk top-level Zensical nav entry. Catalog generation code and catalog/plugins.json are intentionally unchanged; the checked-in catalog can remain schema v1 until the implementation issues update it.

Validation

• make sync in a clean temporary worktree for the committed branch
• make docs in that clean worktree: Zensical strict build reported no issues
• make check-license-headers in that clean worktree: all checked files had correct headers