Improve Vocabularies table readability

[rdhyee]

Wireframe annotation

Hana's note:

"Further divide vocabularies table? Hyperlinks make it harder to read."

Current state

The Vocabularies page (models/index.qmd) uses two Quarto listing tables:

• Core vocabularies listing (3 items)
• Extension vocabularies listing

These are auto-generated from .qmd files in models/generated/. Each row is a clickable link, which Hana feels makes the table harder to scan.

Options

1. Reduce link density — show vocabulary names as plain text with a small "View →" link at the end of each row
2. Group by category — separate Material, Sampled Feature, and Specimen Type into distinct sub-tables or sections
3. Add descriptions inline — expand the table to show brief descriptions without requiring click-through
4. Card layout — replace table with cards (name, description, link button) for easier scanning

PR #93 already wrapped core vocabularies in a collapsible callout and added the ARDC source-of-truth note. This issue is about the remaining readability of the auto-generated listing tables.

Analysis from Figma API wireframe annotation [7:738].