Debugging a Broken Plugin Layout

An engineer builds a plugin with this structure and reports that none of the skills or hooks load when they run claude --plugin-dir ./my-plugin:

my-plugin/
└── .claude-plugin/
    ├── plugin.json
    ├── skills/
    │   └── review/
    │       └── SKILL.md
    └── hooks/
        └── hooks.json

1. Identify the structural bug.
2. Provide the corrected directory layout.
3. After fixing the structure, what command should the engineer run to pick up further changes to SKILL.md without restarting Claude Code, and what's a caveat about what that command does and doesn't re-scan?