Feature Request: Support nested directory structure for skills organization

Problem

Currently, skills must be placed directly under ~/.claude/skills/ with a flat structure. When managing multiple projects, users have to rely on naming prefixes (e.g., linli-bugfix, linli-feature, projectB-api) to organize skills.

This becomes unwieldy when:

• Managing 10+ skills per project
• Multiple projects share similar skill names
• Wanting clear visual separation between project-specific and common skills

Proposed Solution

Support nested directory structure for skills discovery:

~/.claude/skills/
├── linli/
│   ├── bugfix/SKILL.md
│   ├── feature/SKILL.md
│   └── deploy/SKILL.md
├── project-b/
│   └── api/SKILL.md
└── common/
    └── bugfix/SKILL.md

Skills would be invoked as:

• linli:bugfix or linli/bugfix
• project-b:api
• common:bugfix

Benefits

1. Better organization - Physical folder separation instead of naming conventions
2. Clearer namespace - Avoid prefix pollution in skill names
3. Easier management - Can manage/backup project-specific skills as a folder unit

Current Workaround

Using naming prefixes like linli-*, projectb-* to logically group skills.