Plugin marketplace fails to validate git-subdir source type

Description

Adding the official claude-plugins-official marketplace via /plugin → "Add Marketplace" fails with schema validation errors for all plugins that use the git-subdir source type.

Steps to Reproduce

1. Run /plugin in Claude Code
2. Select "Add Marketplace"
3. Enter https://github.com/anthropics/claude-plugins-official

Error

Invalid schema: /Users/<user>/.claude/plugins/marketplaces/temp_1774792552319/.claude-plugin/marketplace.json
plugins.2.source: Invalid input, plugins.5.source: Invalid input, plugins.12.source: Invalid input,
plugins.29.source: Invalid input, plugins.49.source: Invalid input, plugins.58.source: Invalid input,
plugins.63.source: Invalid input, plugins.65.source: Invalid input, plugins.87.source: Invalid input,
plugins.97.source: Invalid input, plugins.105.source: Invalid input, plugins.117.source: Invalid input

Analysis

All failing plugins (indices 2, 5, 12, 29, 49, 58, 63, 65, 87, 97, 105, 117) use the git-subdir source type in their source field:

{
  "source": "git-subdir",
  "url": "owner/repo",
  "path": "plugins/example",
  "ref": "main",
  "sha": "..."
}

The client-side schema validation does not recognize git-subdir as a valid source type, causing the entire marketplace to fail to load.

Plugins with "source": "url" (object) or string sources (e.g., "./plugins/foo") pass validation fine.

Environment

• Claude Code version: 2.1.87
• OS: macOS (Darwin 24.6.0)