Show collection descriptions in the /collections dropdown

[neomorphic]

Summary

On the /collections page, the collection picker previously listed only the collection names, asking users to parse the jargon before knowing what each collection contains. This shows the description inside each dropdown option, with the collection name in bold above its description.

Changes

• Each option in the collection Select now renders the collection name (bold) above its description.
• The closed selector still shows just the name (via optionLabelProp="label"), and search still filters by name (optionFilterProp="label").
• Virtualization is disabled (virtual={false}) so the multi-line options aren't clipped to a single row, and a popupClassName lets the option content wrap.
• Options stay grouped by microscopy type (Light / Electron).
• The selected collection's description also still appears above its release table.

Descriptions come from collections.json (added in the collections redesign), so no new content is hardcoded.

Test plan

• npm start, log in, open /collections.
• Open the collection dropdown: each entry shows a bold name with its description beneath, grouped by type.
• Select one: the input shows just the name; the release table and description render as before.