Claude Code's plugin/marketplace schemas require author to be an object
({"name": ...}), not a bare string — installing any plugin from this
marketplace failed validation ("author: Invalid input: expected object,
received string"). Convert every plugins/*/plugin.json author field
accordingly, and add a build-time check so this can't regress.
Also propagate each plugin's description/author into the generated
marketplace.json entries (not just its own nested plugin.json), matching
Anthropic's official marketplace shape, so the Discover UI shows a
description before install instead of a blank "Plugin details" pane.