- P1: Use root.scope instead of hardcoded 'user' level in claude-plugins provider
- P2: Iterate all registry entries per plugin ID, not just first one
- P3: Add home parameter to discoverAgents() for test isolation
- P4: Add test coverage for claude-plugins discovery (12 tests)
- P5: Cache listClaudePluginRoots results to avoid repeated parsing
Addresses issues found in adversarial review of PR #49
can1357